I think you set a great backdrop for why this happens. They definitely find weakness in homosexuality. And probably resentment too–pissed because they think that gays don't carry their weight in hard times the way “masculines” do.

Also, I believe that societies like that are supreme enablers of those living within. That's how progressive thought is stunted. There is no virtually no dissent, and everyone eggs everyone on. There is too much ignorance for anyone to be motivated to rise above it. I know this is a limp comparison, but it reminds me of a Conflicts of Law class I had last semester. We got to the subject of gay marriage and its recognition in different states, and the professor asked for thoughts on the matter. The first person to speak brought up the slippery slope argument (polygamy's next). That cued a domino effect of other guys echoing versions of the same, as if patting each other on the back. You could hear the intonation in their voices rising, and word choice started getting edgier. To the point where anyone who dared to come at it from the other side would almost want campus security escorting them to their car afterwards.

I think it gets to be a form of bonding for people to align themselves with the popular belief out there. And if there's no one to oppose, ideas just become more radical and cartoonish–but also normal-sounding. Which may explain the dad smiling after arranging for the mob to murder his son. Twisted, sick loyalty to unchallenged absurdities. It's a form of brainwash, and the dad probably honestly thought he was martyring himself.

My work on African-American attitudes on homosexuality won 2 national awards. The origins and nature of the problem include:
1. Christianity
2. Issues w/stereotypes and black sexuality
3. Hegemonic masculinity and poverty
4. Rigid understandings of how blacks can contribute to their respective communities