My response comes down to what I feel the other person’s intent is. If they’re a troll, I don’t engage to begin with - downvote and move on. If we entered into a conversation but I find that they’re arguing in bad faith (they want to argue, not reach an understanding), then I say something like “I’m not going to argue with you about it, but I appreciate your perspective” (even if I don’t). If it seems like it could be a useful disagreement, though, I’ll consciously remind myself that there’s a person behind the text, and I’ll continue the conversation until it reaches an end. It may be uncomfortable, but remembering that we’re all just humans being human helps me tone myself down.
Same, the subscription page is essentially my homepage. It has exactly the content I want on it, and I can always use the sidebar recommendations if I feel like browsing for something new after my queue is complete.