When you have one guy in town that's an idiot, that guy is the village idiot. The village idiot know he's the dumbest guy in town and so will tend to listen to the people smarter than him.

But with the internet you're getting a lot of people together and letting them find groups they fit into. That's mostly a good thing.

But all the village idiots get into a group together where they only people they're talking to are other village idiots. Then they start thinking their idiocy is right. And they stop listening to the people smarter than them.

Then you have a lot of confident idiots who bring everyone down to their level.