I am not Catholic or homophobic and I believe in same sex marriage, so how am I treading on thin ice.

Jim says that Catholicism promises hell for homosexuals.
Is he right or wrong?

Does Catholicism say gay sex outside marriage is worse than straight sex outside marriage?

Many people religious or not oppose same sex marriage, including some gay people. We might disagree with them but it is a legitimate and widely held view. Until recent years it was a universally held view.