Why are religious people scared of...?

I've been wondering for a while why so many people say being gay is a sin. So is masturbating, having sex out of wedlock, getting a tattoo, shaving your beard, oh, and not marrying your rapist, for the ladies out there. A post online brought up some of the ridiculous things that are a "sin" according to the Bible (capitalized out of what little respect I have left), so why are all of THOSE just brushed aside while people nit pick what they want to use out of the Bible for their personal opinions? It's a bit hypocritical, if you ask me. But hey, I'm just an atheist. What do I know?