That ignores the effect of bad actors who will do it regardless though. There may actually be something to using such a score, at least as a qualitative if not quantitative measurement of trustworthiness, like for anyone with a magazine-specific karma score in the negative and spread out over at least ten comments, start hiding their comments by default (like still visible but you have to click to expand now), and allow the mods to decide what their communities rules will be.

Irl it's like: punch me in the face once, twice, three times, and eventually ten times, and maybe one day I'll finally start to think about considering making a plan of action to help you realize that there may be consequences... one day! (maybe) That could help so that if a troll is popular in one place but always shits outside of where they live, those receiving the raw end of that deal could have a way to automatically deal with it?

On second thought though, it's probably too easily gamified, especially by alts created for explicitly that purpose, like it's not that hard to make 10 accounts. But aside from minor UI concerns, something like that could actually change whether/how often someone feels welcomed to go visit a site.

Even back in the old forum days, we had replies akin to "yes, this!" "agreed!" "no" that don't contribute much to the discussion.

So I don't think it's the scoring system that is at fault, but rather it's just human nature. Sometimes people simply want to be a part of something, and those meaningless phrases help to accomplish that.