Ironically, this argument applies to itself, i.e. many people on Twitter are not doing this, and some even strive to "steelman" opposing views. (There is a fundamental asymmetry though: more sophisticated views are harder to understand, thus harder to spread.)
Some people are just at a point in their development where scoring points against the outgroup is the most satisfying thing. I wish I had an easy answer for how to help people cause the least injury to themselves and others as they go through that.
