The direction of my implication comes from observation: text communities tend to all descend into toxicity (observation) -> why does this happen in text communities moreso than non-text communities? (question) -> higher proportion of socially maladapted people (theory). You might well be correct that people who enjoy looking and hearing themselves and have ego issues are the ones that prefer (compose a higher proportion thereof) multimedia social networks. I don't disagree with you, either. That's beside the point. The point is that most text communities tend to descend into toxicity.
Humans aren't perfect and if I'm in a positive community of high egos, I'd much prefer that than a toxic community with "normal" egos.
So I want to zoom in on this:
> Some people like to take time to compose thoughts in written form because that is generally the best way to communicate thoughtfully. You can say what you will about a lack of body language, but plenty of people get into verbal fights in person and it doesn't help that they end up talking over each other.
We're talking about social networks here not real life, because social networks deal with the fundamentally different problem. In a social network (yes this includes IRC) you are interacting with a number of people whom you do not share any real-world context with, whom you do not share any physical space with, and whom generally have a much lower stake in their relationships because of the lack of shared context.
In my experience all textual social networks that grow beyond a certain number of users descend into toxicity: Usenet, IRC (old Freenode and Rizon), Slashdot, Digg, Reddit, HN, Youtube Comments, Nextdoor, Local News Comments, Twitter/X, etc. I think "algorithms" (including counting upvotes) have reduced the moderation burden and allowed social sites to scale much higher than they could before algorithms.
Text communities all eventually collapse into ranting, bullying, hot takes, moral outrage, zealotry, and negativity. I'm open to any and all theories about why this is but I find this specific to text-based communities: Twitch, Instagram and TikTok have so much less of it for example. I think the idea that text leads to thoughtful communication was a hypothesis advanced first during the Usenet era and later during the blogging era but ended up being disproven. I think there's a nostalgia of the pre-media web that pervades these discussions that prevent text-fans from realizing at a macro level that the toxicity that was on comp.lang.lisp is the same toxicity in HN comments and is toxicity that just isn't there on most of Instagram, for better or for worse.
I actually think this identity around being a "text person" is part of the problem. The moment you wrap your identity around something you become both proud and protective of it. For some things this is fine, but if your preferred media itself becomes part of your identity, then you're going to have a blind spot around what makes your preferred social media different from the others.