Yes, don't you see the correlation there?
Personally, I think all forms of religion are silly. But they are a protected class in the US, just as sexuality is. Legally speaking, both can suffer discrimination.
I would say they are inversely correlated. Discrimination is always going to exist. It is human nature. However, I think that the law needs to side with the one being discriminated against and not the discriminator.
I will agree with your second point. Christians can be the victims of discrimination just as much as anyone else. Ironically, the perpetrators are often the same people who are against bigotry against Muslims, minorities and gays.
I really don't see this law as being about religion though. It just seems that religion is being used as an excuse for bigotry. If it was about religion, then shouldn't these businesses also want to ban adulterers, divorcees, people who eat pork, those who covet their neighbors, those who engage in usury, etc.
I also don't see how this law would be enforceable. Are business owners going to refuse service just because someone seems gay? I have met many effeminate straight men in my day, and also many gay men you couldn't pick out of a lineup. Where does it stop. What if Muslims don't want to serve Jews, or Protestants not wanting to serve Catholics, or Scientologists not wanting to serve Hindus. The whole concept seems stupid and has the potential to get out hand. Is the day going to come when I have to make sure all of my political and religious beliefs must match a shopkeeper before he will make me a sandwich?