Yeah, I mean that's true of any social space though, if you say something agreeable (definitionally) you're going to get agreement. If you view upvoting as consensus building (i.e "I like this" / "I agree") it's just a more concise representation of a reply saying as much.

But that is scrutable.

What becomes a problem is content getting surfaced/buried on non-scrutable metrics (typically engagement) — ragebait isn't anything new, online or in societies. But when algorithms target content that gets engagement, ragebait is naturally surfaced in higher proportions. Often time such platforms completely bury content or make it impossible to find something not explicitly surfaced (YouTube search for example is widely known to be terrible here, FB rabidly buries comments on posts).

WRT communities, there definitely are instances and communities with very different rules, values and expected behaviors. Federation allows communities to pick and choose what other communities they think they'll get along with. This includes banning individual remote users if they don't follow local rules, or defederating entirely if other instances have drastically different values.

The federation model as described does well by my metrics. I can pick an instance that shares my values, participate in communities (in the Lemmy technical sense) that share them as well — and largely avoid or choose not to engage with people from communities (in the instance sense) that I don't share values with. This is extending "freedom of association" to online spaces in a way that large platforms largely cannot and willingly do not enable.