@Demosthenes in the past there was no Internet, so your community was confined in the people you could physically meet. So if you had an unpopular or problematic idea, you couldn’t express it anywhere if your community was against it. You either tried to get over your idea or just lived with it alone. But the coming of the Internet means you can always find what validates your belief just by a few minutes of searching. You don’t have to travel far away to find someone like-minded, all you need is an Internet connection and a device that can connect to the Internet. While this has a positive effect of giving the voiceless a voice (like people suffering from mental health or discrimination that was acceptable in the past), it also has a flip side of connecting the crazies together and make them think they are right in their crazy belief. Sure, social media do push crazy ideas into people because the algorithms need to make sure they stay on the site as long as possible, but where do all the contents come from? They are all make by people who have crazy ideas and want to share them with like-minded people. If no one made those contents the algorithms wouldn’t have anything to push on people even if they wanted to. And the side effect is that people who would otherwise be neutral are dragged into the mud with them.
Not to mention the Internet can be very ambiguous when it comes to satire. A sarcasm can be misunderstood as genuine. I read somewhere in a forum that said something along the line of “try to be dumb for fun and actual dumb people will think you are on their side”. People who already have problems with reading emotion and detecting jokes are even more confused when face with a wall of text that sounds serious but isn’t. And if those people make it a goal to find just about anything to validate their existing bias, that would even be more dangerous. That was what happened with the Canadian van murderer, and that was how we got the Pepe the Frog statement.
Dumb people have always existed throughout history. The Internet just helps gathering them all in one place and make them more powerful while thinking they are on the right.