Because in order to federate, user data needs to be shared, including the username. It prevents double votes from the same account and also allows votes to be rescinded at the user’s discretion, at which point the instance will send effectively an undo signal for the activity.

The first rule of the Fediverse is to make sure you’re perfectly okay with the entire internet seeing your account activity, including votes and favourites. If you’re unsure or are worried you might regret it, best not to post it at all. This is equally true on all social media but the way the Fediverse works just makes it more obvious.

imagine people would start defeding email

There are literally globally maintained blacklists of spam email sources. When people lease a static IP address the first thing to do is to check it against the major email blacklists.

Block 'em and move on I say. It’s clear there’s no reasoning with them and there isn’t much we can do to stop them from spewing propaganda at us. In fact, engaging them will probably only exacerbate things.

Us: “China isn’t committing the atrocities the West accuses them of and here’s evidence.”

Anti-China people: “OMG you actively advocate for China’s atrocities and want them to keep happening!”

It’s ironic that the “OMG CHINA IS GENOCIDING” crowd accuses us of lying and ignoring evidence when we tend to be the only ones providing sources for our claims. It’s evident in this very thread.