I always have to think about that one when I had just been spending 20 minutes trying to formulate an elaborate response to someone's comment, just to proceed to sigh and close the thing without posting it. Probably most of the time it was for the better too.

I'm self culling a lot more too. I'd argue those unposted drafts are still valuable, if only to help oneself flesh out ideas.

I completely agree. Often I don't proceed because the point I wanted to make is just not properly defendable at that point. But the ideas written down in the process don't disappear and at the same time I got a better appreciation of the other side's point of view. I'd rather hold on to those ideas and evolve them further than to get too attached and be forced into a situation where I eventually defend my opinions because I moved myself into a position where I feel like this is a deep personal belief rather than a well defined objective-ish argument I tried to make.

Where do you draw the line between someone on the internet "being wrong", and someone on the internet spreading dangerous misinformation? Sure, walking away from the first is often a good course of action, but what about the second?

It's often very hard to tell the difference. If I ever find myself in doubt, I try to default to walking away. Not always successfully.

Same here. I often joke that I should keep this one posted at my desk. It helps remind me to walk away.