Oh yeah, most social media sites are way worse in terms of the risk of bullying and dogpiling and such. "Just block people" is generally good praxis, but it's not a be-all end-all solution, either.

LJ definitely had its fair share of toxicity, as nostalgic as I am for it. And I think you're right - while the toxicity there was much less than modern socmed, there were already quite a lot of hints of the things that have simply been magnified now. I think that's why I feel so bad for the people being forcibly uprooted from Twitter now - it was a toxic space that I think we're better without... but that isn't much comfort to the people losing a space they'd cultivated and connected on.

I do hope more people join DW. I always hope that. I think it's a better format that's less prone to the "hot takes" and vitriol of twitter, one that allows for more personal, ongoing communication with people in a way that isn't as public as reblogs/twitter back-and-forths/talking in a discord channel, while also not requiring the conversations happen in private via DM. It's better for community building and potentially finding some new person that you'd be interested in knowing better.
Double-edged sword in that it requires more personal effort to find and make those connections though, and that I see a surprising number of younger people talk about how the site seems impossibly confusing.
Older fans (the target DW audience) are broadly more chill (though the ones that suck still suck bad), and younger folks who are willing to put in some effort to figure out how to use the site also self-selects for a hopefully better crowd.
BUT it also means that a lot of people WON'T be willing to put in the effort required, and it's hard to get the kind of community engagement people are looking for without newer and younger people ever joining.
(Though I'll take quiet-but-good over active-but-toxic any day.)