The important thing would be for moderators to be able to police "what is liked/disliked". Hear me out.

If you've got this space where dozens or hundreds of people all have a high overlap of favorable content, but there's this one turd who comes in and downvotes everything, always... he's not just a little different, and he's not assimilating. He's trying to sabotage. If this was visible to a moderator, that moderator could decide he doesn't belong to the group. I don't advocate that he no longer be able to view the content, but maybe his votes just stop counting. Maybe he's no longer able to post content of his own (would be up to the moderator, I think, perhaps his content was always good enough, but his voting is counterproductive).

I think that on places like reddit they avoided this functionality because it would give moderators too much control over their communities, and outsiders would be unable to come in and eventually take over and force the original group out. Being admins, they could of course have done this anyway, but it would require them to be heavy-handed and obvious.

I think, if you have a saboteur, they're probably not part of your 'network'. The people you've endorsed probably won't have endorsed the saboteur, so the saboteurs activity should not effect your feed in any meaningful way. This is how trust works in real social circles.

Moderators clearly work but it's a shame it relies on single people doing a good thing. It's a shame the moderation can't be done by everyone all the time, unconsciously.

what you describe is called "shadow banning".

https://en.wikipedia.org/wiki/Shadow_banning