That’s a very interesting suggestion and I’d love to see it done, actually, regardless of what I’m about to write.
The problem is that mods aren’t bot sweepers or disinformation sniffers. They’re just regular people… and there are relatively few of them. They probably have, on average, a better radar than most users, but when it comes to malicious actors they aren’t going to be perfect. More importantly, they have a finite amount of time and effort they can put into moderation. It’s way better to organically crowd-source these kinds of things if it’s possible, and the kind of community Lemmy has makes it possible.
Banning these comments makes the community susceptible to all kinds of manipulation, especially in the run-up to a US election (let alone this one). The benefit of banning these comments is comparatively very minimal: effectively removing one type of ad hominem attack in arguments that have always featured ad hominem attacks, in one form or another.
How would backing up help with that, though, assuming the backups are also encrypted?
If they lose the key they lose the data in the backups, too. So that concern is not a good reason to backup, in my eyes.
Then, if the backups are not encrypted, then doesn’t that undermine the value of encrypting your drive/user data partition in the first place?