While pop culture embraces sexual liberty as innocent fun, such promiscuity leads normally sensitive people into conflict and heartbreak. That's why God prohibits fornication; straight or gay, it's sin.
Fictional literature requires conflict--sexual or otherwise--and sin produces conflict. Since God requires His people to set their minds on things above, does that prohibit our consumption of literature? No more than it prohibits our consumption of Bible stories that deal with sin.
Of course BROKEBACK MOUNTAIN can't be compared with the Bible, but to the extent that they are honest storytelling the same principle applies to both. Does this mean I wink at depictions of homosexuality in the entertainment media? Not at all. Sitcoms portray gays as cute, funny, or artsy--anything but the flawed human beings they are. If Hollywood presented a balanced picture of homosexuals and their lifestyle I might spend some time watching it.
Moral reprobation--gay or straight--is not funny, but that's not to say tasteful humor will never be involved in its portrayal.