Don't hate religion, hate the misteaching of it.
I doubt very many of those people are against homosexuality because of their religion. We live in a modern day world where we are allowed to think for ourselves. Anybody who's willing to look into the Bible will realize that 1.) We might be taking it out of context, and 2.) The amount of verses related to homosexuality simply do not warrant all of the supposedly religion-related homophobia. Especially not when so many of these homophobes blatantly ignore sins that are on the same level. All of them do.
I mean.. If one is going to pick and choose (which all Christians really have to... You simply can't follow the whole book, and I seriously doubt that the vast majority of Christians have any clue what all of the things that the Bible preaches against are.) then one should pick and choose the good.
But of course these people don't. Why? Because they have something against homosexuals to start with. The majority of these people only care about the sins that denounce things that they are personally against.
So in reality, they are not religious beliefs, and they simply should not be respected as religious beliefs either. I know that there are some kids that probably honestly believe that homosexuals are going to hell because they were raised that way, but eventually they'll have to grow up and actually read their Bible. But then it's just a result of misteaching.