Meh, some sort of good spam filter + good moderation (not of dissident opinion but of pure trash, oneliners and other boring stuff) and you'll resolve most issues, at least when it comes to blog comments.
And we managed to moderate it well. Granted, the community has ~100 moderators who are all doing it in their free-time, but with the right tooling and the right guidelines/rules, moderation is not impossible. It's just really hard to get right.
Most recently, the author of the basement community site documented their dealings with some when their site got popular, which included someone(s) of an anti-social bent. The cynic in me saw that coming from miles away so it's no longer a surprise, but in reflecting about 25 years of Kottke.org, actually, yeah it is.
https://basementcommunity.bearblog.dev/things-i-learned/
(posted here at https://news.ycombinator.com/item?id=35132223)
Indeed, it is possible. My blog (pretty much unchanged in format since 2004) gets around 500 page views/day and averages ±10 comments/week. Just right, small enough that I can respond personally to comments.