Why do some fundamentalist/evangelical Christians say s are going to hell?

Even if they believe that uality is a sin which I don't think it is, even if it is sin to them, the bible says that it is not living in sin that gets one to hell but lack of belief in christ as the savior. Some of these folk should realize that if they actually followed their book that according to their own bible a gay christian is more likely to go to heaven than a straight non-christian.