Just because a Christian perceives homosexuality as sin doesn’t mean he is justified in any level of intolerance, and just because an atheist/agnostic knows a Christian sees it as sin doesn’t mean that Christian is hateful. See _ender, darth.
The point is that calling it a sin can (in certain deranged people’s minds) justify hate and violence, and that makes it hate by extension at the least.
I really hope that the modern-day Pharisees will come to see things differently. I believe loving our neighbors should always prevail as God’s second highest law (to loving him of course), trumping any interpretation of what is sin.