Mastodon is a bubble. You have primarily highly educated, tech-literate nerds on that platform.
Obviously people are more civil and polite there, than some raging uneducated losers and trolls on facebook.
As the fediverse grows, the userbase will obviously lose this current isolated tech-wizard school vibe, and feel more like going into a random pub in a big city. Regardless if Meta joins the fediverse or not.