See, secularism isn't a religion, it's just not.
Religion is a belief in a higher, spiritual being and all of the cultural and dogmatic practices that go along with that core belief. Secularism is simply the separation of religion from government.
Put another way, if government is a glass and religion is water and a theocracy is a glass full of water, then secularism is the act of keeping the water out of the glass. Now, you can call that empty glass anything you want, but it's not a drink of water. Believing that religion and government should be separate is not a faith, it's not a religion. There is no "church of secularism", there is no covenant, no bible, no doctrine, no prayer meetings, no secular heaven or hell, no secular God, nothing. Secularism is not a religion, it is the separation of religion from government and nothing more.
Secularism is a wall that keeps religion on one side and government on the other. If religion was cows and government was pigs, secularism would be the fence that kept the two animals separate. Now, would you call that fence a cow? Of course not, because it's a fence. The argument that secularism is a religion is calling a fence a cow just because it keeps the cows from mixing with the pigs and that's obviously ridiculous.
This is a fairly common mistake or deception, you decide which, that conservatives use not just for secularism but for atheism as well. Conservatives like to insist that atheism is a religion and that not believing in the existence of God is one's "faith". Again, this is a completely ridiculous notion. You can call atheism an opinion, you can call it an ideology, you can even call it a belief - albeit the "belief" in nothing, but it's not a religion. Just like with secularism, there is no church of atheism, no atheist bible, no atheist doctrines or commandments. Having any of those things would make atheism a religion and it's not a religion.
To argue that Obama is pushing an agenda of secularism is viewed as a negative criticism to conservatives, and that's not surprising. Conservatives want to incorporate their predominantly evangelical Christian beliefs into our government. They want to impose their personal view of Christianity into the legislative process, so of course anything that would seek to block those attempts would be viewed as an attack on their beliefs. However, the separation of church and state is clearly defined and was the original intent of our founding fathers when they established America as a free country and, specifically, when they made the topic of laws and religion part of the very first amendment to the constitution.
Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof
That, in itself, is a secular statement. "Congress shall make no law respecting an establishment of religion" This means, in no uncertain terms, that congress will make no law that either encourages or prevents the formation of any religion. Congress will stay out of the religion business, it won't tell you what you can believe and it won't tell you what you can't believe. Thus, religion and government will be kept separate. This is the textbook definition of secularism.
"Or prohibiting the free exercise thereof" Again, congress will not tell any American that they cannot believe what they want or practice their chosen beliefs as they see fit. However, there is one caveat to this freedom - you must obey the laws of the land.
Our laws are written so as not to deliberately infringe upon the free exercise of one's religious beliefs. They are also written so as not to impose a religious belief on anyone as well. This is why many politicians who are men and women of faith and who attend church services in their personal lives can be pro-choice when it comes to their legislative policy, or support gay marriage or any of a host of other social issues that might conflict with their personal faith. It's not because these are evil, godless people, it's because they recognize that they are bound by the constitution not to legislate either for or against a religious ideology - or lack thereof.
There are people in this country, for example, who are strongly opposed to abortion on ideological, religious grounds and there are people who do not view abortion as a religious issue at all and support it and there are the vast majority of Americans who fall somewhere in the middle on this issue where, like myself, perhaps they are opposed to abortion as a personal decision, but are equally opposed to the government stepping in and taking away the right of someone else to make a different choice than we might. It's not just abortion, either. Lately, the topic of contraception has become politicized and the argument about whether a religious group that runs a non-religious business should abide by the same laws that govern all other non-religious businesses in this country, but the core of that argument is the same - government makes laws regardless of religion, they are just as bound to not cater their legislation to any one religion as they are to not legislate against it.
This is a point of confusion for a lot of conservatives who believe that the Obama administration's recent - and amended - ruling to make all employers of non-religious businesses provide health insurance that covers contraception is a deliberate attack on the Catholic church. It's not.
First of all, it's not even an issue anymore from a legal standpoint because, as I mentioned, the Obama administration has already amended their ruling to shift the financial responsibility of covering contraception to the insurance companies when it conflicts with the religious beliefs of the employer, so there's no longer a legitimate "violation" of religious beliefs for the Catholic church or any other religion. Secondly, though, it's not a specific attack on the Catholic church, so it's not a law that prevents the "establishment" of the Catholic faith - because it already exists - nor is it a law that prohibits the "free exercise thereof" of the Catholic faith, because the law does not force Catholics to use birth control. Asking an employer of a non-church business to provide the government-mandated health coverage for their employees does not obligate the church itself into a position of making any moral judgement call on the nature of that coverage whatsoever.
Here's another example to illustrate my point. The Mormon religion prohibits drinking caffeine. However, it does not prohibit it's members from working for Coca Cola or working at a supermarket that sells Coke products or driving a delivery truck that takes Coke to stores or being a barrista at Starbucks. Literally, there is no difference between requiring Catholic employers to provide contraception coverage and requiring a Mormon who works at McDonalds to serve Coke to their customers when they order one. In both cases, the individual is being asked to make available to someone else an item which their personal religion is opposed to the use of. Now, obviously, there wasn't a massive politically-driven attack against the government by outraged Mormon church leaders who wanted special exemptions to keep Mormon employees at businesses that sell caffeinated products from being "forced" to serve those products, because that would be ridiculous. Serving a caffeinated drink to another person does not violate the Mormon church's own rules against it's members drinking caffeinated products.
Likewise, requiring Catholic employers and universities to provide contraceptive coverage to non-Catholic employees and students does not violate the Church's own laws against it's members using contraception. Never mind the fact that something like 96% of all Catholics use some form of contraception, we're not even talking about Catholics using contraception, we're talking about non-Catholics who work for a non-church Catholic-owned business or attend a Catholic-run university.
In other words, if the Catholic church in your town buys a Subway and hires a Christian employee to make sandwiches, they have to provide a health care plan to that employee that covers any contraceptives they might use. This doesn't force a single Catholic to use birth control and thus violates nobodies religious beliefs. Catholics might have a problem with contraception, but their rights don't get to supersede anyone else's, because that would be a law "prohibiting the free exercise thereof" of someone else's religious, or non-religious beliefs that allow for the use of contraception.
So this brings us back to secularism as a non-religion, because that's what secularism is, not a religion. I'm not sure if it's just that conservatives aren't capable of processing the notion that people can hold beliefs that aren't rooted in a supernatural deity, or if they're being willfully obtuse, but it seems that many conservatives are not capable of wrapping their heads around the concept of having opinions about religion that aren't, themselves, part of a different religion. Thinking that religion should be kept out of government is not, itself, a religion. The fence is not a cow.