We also do it to ourselves. Everyone has someone in their life they'd rather mute. But they're forced to coexist with them. Online is so appealing because you can find communities of like minded individuals. Then forget all about those other opinions you don't like.
You grow in this bubble as they grow in theirs. By the next time you're forced to interact, you feel so alien and unpleasant to one another it's confusing and frightening. Corporations are right there to sell you on a story about how the other side are demons destroying the world. We gobble it up.