Something you may not know about guys, a lot of guys at least, is that we start viewing porn generally from our early teens, so, over the years that Man Woman porn doesn't do it anymore, you know, it can get stale and boring.

That is sort of the danger with porn nowadays, it is so varied that you can find some pretty intense shit.

This is basically a long winded way to say that he might not be gay, instead, the stimulation he receives from porn is numbed and to achieve that same level of stimulation that he used to, he views more and more intense shit.

It's like saying because you choke your partner during sex that you want to beat them outside of sex.

EDIT: Teen stuff is a buzzword in porn, it usually means amateur, not industry produced, even so, half those chicks look like their pushing 30. I don't personally seek out teen stuff, though it is pretty common in titles.