Partisan argumentation was f2f, in self-selecting meetings. I suspect some of the things said in some of those contexts were far more extreme than is common today - but the median today is likely more polarised and heated.
I was on AOL in the mid-90s, and some parts were at least as toxic as Facebook.
Ultimately it's set by the quality of the moderation but also by the quality of the people. You need people who have some self-awareness and restraint, and who can tolerate dissenting views without exploding all over them.
I've just watched a music forum explode. The mods couldn't quite work out how to handle a difficult situation, there were wildly polarised views, and virtually everyone seemed to be operating from negative assumptions and bad faith without actually listening to what was being said.
It was honestly one of the ugliest things I've ever seen online.
Does it matter? I think it does. Civility is the foundation of culture. Most people at least attempt it, with varying degrees of success - but some people really aren't interested in it, because they prefer their hit of outrage.
I can't see how that can possibly be a good thing. Even if the aims are good, the means are mean and there's a general reduction in empathy and collective intelligence. None of these are good.
I really don't know how we get past this. Maybe we don't, and various bad things have to happen before that becomes an option.
But I am absolute sure now that the influence of mass social media is almost entirely toxic - like tobacco for the mind. The industry badly needs regulation, de-monopolisation and federation, but it's very hard to see that happening.