I think part of this also stems from there being a lot of strong takes on certain subjects that appear in comments. Thinking of just the past few posts I've been through, I've seen statements (which i'm intentionally paraphrasing here, just using them as examples) like "all information should be free", " is better than fad languages and all opinions to the contrary are completely unbacked" (different instance to be fair), "X service should be provided for free by Y private company", etc. That's not to say that any of these takes (except the language one, in my opinion) were intentionally inviting people to debate them, but making strong claims like these does invite debate.
That being said, I think the purpose of a lot of posts is to invite discussion, and within those discussions I've often seen people agreeing with each other. From my experience, it tends to be more of an outlier when there are argumentative posts being made, but I think it stands out a bit more as well.
Also, I think that how the opposing view is presented is important. For example, I'd rather see a response that opposes an initial view to provide more discussion around the matter than "no you're wrong and a bad person"-style responses. Generally speaking, I've seen more discussion-oriented replies, but occasionally I do see the latter-style response as well, and even saw one (which I'm not pointing to) in the discussion for this post.
Edit: I should also clarify that first paragraph. Opinions to the contrary of what I listed can also be strong takes. Generally any opinion in which there is a significant population of people that disagree with it can invite discussion. The discussion itself isn't the issue in my opinion, what is the issue is how that discussion is held.