Comments sections on mainstream sites are universally garbage dumps, and you just have to ignore them. I don't know why sites even add them. Must be some "best practice" from Web 2.0 back in 2004 that nobody's questioned ever since.
Someone on HN asked me "What's the point?"
Depending on the site and community, a comment section vs needing to find a way to email or phone or meet someone in person in order to give them something is often a make or break threshold for contributions. Sadly, it's often also the threshold for bad contributions.
But why do sites do it? Yes, like another commenter said, it boosts engagement. Both for the platform and the users. Creators and commenters and even lurkers.
If you're gunning to be a creator with an audience, I don't think the answer is to completely ignore your audience. It's to learn how to cultivate a target audience, how to not engage with malicious people, how to be strategic about your messaging, outreach, branding...
Of course, if you're not interested in those (truthfully tiring) things, then your rule of thumb is a pretty good one for most people.