In my experience it's more of a pushback or contrarian dynamic. The first wave of comments tends to be negative as people object to the article (unless it's particularly interesting, which is the case we hope for), and the second wave tends to be positive as people object to the objections.
You're right about the upvoting though. Bad upvotes are a bigger problem than bad comments. ('Bad' here means 'not helping with intellectual curiosity and civility'). If you put that together with the pushback thing, it explains a curious phenomenon: why at the top of so many active threads sits a comment saying "I can't believe how negative the comments are here". It sounds self-contradictory but it's not, because there are multiple generations of comments. That's a pushback comment attracting a lot of pushback upvotes.
You're right about the upvoting though. Bad upvotes are a bigger problem than bad comments. ('Bad' here means 'not helping with intellectual curiosity and civility'). If you put that together with the pushback thing, it explains a curious phenomenon: why at the top of so many active threads sits a comment saying "I can't believe how negative the comments are here". It sounds self-contradictory but it's not, because there are multiple generations of comments. That's a pushback comment attracting a lot of pushback upvotes.