It might actually reflect your own prejudice a bit that you're interpreting it that way. Speaking as a rainbow myself over here, it's...not unlikely? Throw a bunch of teenagers or young adults in support groups together with the subtext that they all have the same sexual orientation with no chance of being shamed for making advances for what's effectively the first time in most of their lives, and it doesn't take a fortune teller to figure out what's probably going to be happening in greater rates for those kids.
And there's definitely evidence that lower academic investment is correlated with higher sexual activity; I've been up for dozens of hours now so forgive me for not throwing some papers in your direction, but they shouldn't be hard to find.
I don't think it's healthy for anyone to really analyze this stuff for any demographic, but acting like what he said was so awful was really out of line, and pretty clearly breaking HN's guidelines.