You're right about Hollywood but their audience has been set up for them by previous parents who let the larger culture and schools instill values in their kids.
BTW Brokeback Mountain has more than doubled its production budget at the box office. That makes it a financially successful film.
It depends on marketing costs which can run up to $40 million. Since Brokeback has gotten so much free publicitiy, I doubt marketing costs are that high. Overall, the movie will turn a profit, but not be a blockbuster.
Syriana still has only made $44, while costing $50 after 7 weeks. Munich only made $32 while costing $70 after 4 weeks. Those two will likely lose a bunch of money.
So America might see a gay movie, but still rejects anti-American, pro-Palestinian movies....which is nice.