The demographics of the internet users have changed over time. At the beginning it was researchers, then graduate students, then normal University students. Then the affluent civilians, then the metropolitan civilians, then everyone.

Each of those demographic changes, includes a shift in the average discourse. The way researchers disagree with each other heatedly is going to be different than the way the common person disagrees with other people.

I would argue the state of the internet discourse, is a commentary on the state of direct democratic discourse. Many people are simply not equipped to have a constructive debate.

Of course the algorithms in their pursuit of engagement, just magnify this effect ensuring that the most outrageous of commenters get seen by the most people.