You can blame this on Russian and/or Chinese disinformation ops and tik-tok, etc, but the problem is more general than that. One of the assumptions around free speech ideals is that the people who are speaking or publishing are citizens of the community in which they are speaking or publishing, and now a large part of the content on the internet is produced by people who are crossing national boundaries, or not even produced by people at all.

You used to be able to assume that the vast majority of the content you're exposed to is produced by people who live in your community or country and would not like to see it destroyed, and now, in fact, you should probably assume the opposite. You should assume that most content on the internet is produced by bad actors trying to rip the fabric of your society apart, particularly if you're reading something that enrages you.

The especially insidious part of this is that most of the rage bait stuff plays on widespread personal biases so it's self sustaining after a while. People start to hate each other, so then they do stuff to each other to make each other hate each other more and so on and so on until you've got Rwanda.