How is the "First Amendment Defense Act" not a blatant attempt at imposing Christianized Sharia Law?

Republicans recently put forth legislation that legally protects those that oppose same-sex marriage and premarital sex from being accused of discriminating against homosexuals, single mothers, and basically anyone who they don’t like.

I can see no reason for this legislation except to weaken secular government in favor of strengthening the role of religion, not unlike Iran or Iraq, but there may be something I am missing.

Can someone please enlighten me as to how this isn’t basically a way of saying, “This is Jesus’ country, we can do anything we want, and there isn’t anything you can do about it!”? Or am I correct in assuming that this really is a blatant attempt at turning our Democratic Republic into a Theocracy?