When I ran a science forum, I found that topics on what could roughly be called "science and public affairs" seemed to draw traffic. The problem with pure science topics is that one person has a deep, decade-long fascination with, say, polydactyly in cats. That's a nice niche for them, and they draw a few participants for a week or two and then the thread quietly fades. However, start a thread on "Transgender physiology and sports rules," and that baby will thrive for years, with hundreds of posts per year, and all kinds of ancillary issues drawn into the discussion. (it will needs lots of moderation, too, and the bouncer will need to be called occasionally, but overall there will be a lot of learning and sharpening of vague intuitions people have).
Up the thread someone (Wegs? sorry, just starting to remember the names) mentioned that threads where there's bullying tend to make visitors doubt about staying around. Even low-key and righteous bullying ("you are just dishonest, as you always are, and I'm going to remind you of this daily") tends to dampen the impulse to join a thread. Yes, you want to call people on bad faith arguments and sloppy reasoning and so on, but at some point maybe it is better to just tune them out or, if a moderator, just delete posts that don't meet basic forum standards and let the poster know why and what is expected.
Those who equate forum rules of discourse and standards (peer reviewed citations, say) with "censorship," will tend to move on.