Yeah I expect given how long ago IRC's heydey was, we're talking about quite a different demographic. Everyone I know who used it was on the nerdy side (this includes me, it's not an insult!), whereas things like Discord with their modern interfaces make things easy enough that for example I run a crafting community on there full of old ladies sharing their cross stitch.

Anything that attracts huge numbers of regular folks like that is gonna be a target for trolls and spammers and suchlike, so without good moderation a public server can spiral down quite fast in my experience. Add to all this the ever-increasing hostility and us-vs-them of people on the internet in general, and ugh.

I'm sure there are plenty of lovely spaces out there too ofc, it's just finding them that's the trick :)