For example: removing anything related to Mangione’s manifesto or “glorifying violence”.

I was asking in general, thank you for the extensive answer.

Does anyone know which Lemmy instances are censored?

Unfortunately, Firefox is not as efficient as Chrome. On a battery powered devices this matters. Also it doesn’t have a native dark mode for web content.
I’m this close to jumping the ship.

They do have the choice. It doesn’t mean that everyone has to agree with or respect that choice.