That would imply that the world consists only of alt-left and and-right people. In reality the vast majority of people are pretty moderate, and there are far more than two political directions.

Most dramas on Twitter or Reddit involve some one- or two-digit number of people that get enormous publicity.

I don't think my comment would imply what you describe. I think it would imply at least (but not exclusively) the existence of 4 diffuse groups (Left, alt-left/moderate/centre-leaning-left, alt-right, right), just that Twitter and Reddit are cesspools where the loudest of the Left yell at each other for no other reason than nobody else will listen, because they've all been forced off or quit of their own accord.