...right from a pro-jw site in response to a post about the relative seriousness of homosexuality
All you can do is reason from the scriptures, which you appear to have done. Homosexuality is as serious as bestiality, or adultery and fornication. Actually, the Bible describes homosexuality as a greater sin than adultery or fornication. The reasoning is that the desire for same-sex intercourse is one "contrary to nature" according to Romans 1:24. At least with heterosexual fornication the wrong doers are acting in harmony with the natural desire for the opposite sex.
I'm sorry to post direct cut'n'paste but I think it's important for people to see the thinking that "mature Christians" continue to have regarding homosexuality. It's probably not news to many but does demonstrate that ones continue to treat homosexuality as different to other sins and how blurred the lines around hating the sin and not the sinner really are.