@Yell,
1. The U.S. founders were flawed human beings who weren't omniscient or divinely gifted, and like humans, they often contradicted their own principles by shoving them under the rug, which later became enshrined in precedent.
2. While National Socialism isn't a religion per se, it was not scientific and it had a lot of the same faith-based qualities of religion.
@BeoWolfe,
Keep in mind that I later revised my statement to "regulate religious expression in public spaces," because I realized that I was too hasty in my conclusion.
No, an afterlife does not scare me. For me to accept a belief, it must satisfy the following conditions:
1. Logically consistent
2. Coherent with our best empirical knowledge
3. Empirically testable
4. Parsimonious
Since religious beliefs badly fail these conditions, I reject all religious beliefs. Of course, that doesn't mean you can't express your religious beliefs. What you can't do is coerce or pressure others to participate in religious activities in public establishments (business, education and government), discriminate against people based on their religion in public establishments, have the state benefit or contract with religious institutions, or allow such public establishments to host religious activities in public spaces.
Other objectionable things that need to be dealt with are:
1. Religious politicians and leaders who call Atheists or Muslims evil or un-American.
2. Government funding of religiously-inspired and unscientific policies such as abstinence only education.