The way I read it, 4chan is like a concentrated version of what it was like to be a teenager at the edge of society. You stir the pot and feed off the energy that people respond with.
If you live in a Christian conservative community, you leave pamphlets full of gay porn outside church. In a progressive community, you make racist websites about interracial dating.
They aren’t pro gay porn or pro racism, they’re pro getting a reaction out of people, that they find hilarious. We encourage them with our outrage.