CGP Grey’s video offers both explanation and examples, and helps explain why Americans mostly don't know about the topic. i.e. it was used by people in the North to protect slaves running away, but also by people in the South doing lynch mob activities - either way, it reflects a breakdown of all of society and complete and utter lack of trust in the governing bodies, and a lifting up of personal preferences above the needs of society, to the point of even lying to a judge to accomplish the end goal.
i.e., totally setting aside right vs. wrong, there is a process by which things are most helpful to happen - e.g. voting, and in this case a trial by jury - and this topic completely bypasses that process. In short, it claims that the end justifies the means.
And that is a very dangerous topic indeed. As with the mod on LW, who gets to decide those ends - the Christian God? And who speaks in His place then, you?
Things like AskUSA or USAFinances could go pretty much anywhere. And even USpolitics does not have to be so problematic. But it sounds like you want a space more for international people to talk about international matters, not only in relation to the USA, though perhaps sparked by events happening in the USA, at least for today but for tomorrow perhaps it will happen elsewhere.
People discussing things in good faith can do so easily and anywhere, I generally find, but the problem with social media is that people who refuse to restrict themselves to good faith discussions will join as well. So basically you may be wanting 4chan, except without the toxicity - but that's not how that works, it would take enormous efforts to build something like that, which could be done but would be supremely difficult especially with the tools offered by Lemmy?