I don't believe this is true. I remember "Ye Olde Days" (TM) of the Internet. You went to an independent forum or mailing list that supported your interest (video games, music, politics) and then you argued with everyone in your "tribe" about video games and music and politics regardless of the purpose of the forum (which is hilarious and endearing to me). You had friends and you had frenemies but you didn't have strangers. It was nice. It was a community. Some interest brought you all together but you didn't stay there solely for that interest. You stayed for the people.
Now what do we have? Complete corporate domination and centralization. All interests are segmented into hashtags and subreddits but exist in the same super-massive platform. And there conversation is moderated by two entities. Moderators and the mob. There is no community anymore because the community is too fluid and too large (sometimes its everyone on the internet). You don't know the people you argue with. And so argument can never be taken on good faith.
You know, I had more stuff written but can't quite complete the thought in words. I think I'll just make an alternative.