It's all about controlling the narrative. Historically the narrative was a battle of ideas, with the best ideas winning out because they were more convincing. Recently, however, the left has taken the tactic that using convincing arguments is not the solution. Instead, the solution is to marginalize the opposition so that they will not be heard, or criminalize their speech.
Think about it. That's an easy solution for them because it means they don't need to construct convincing arguments anymore.
Of course, if the left can't construct convincing arguments but still wants to control people, what happens? Rule by force. Violence. Basically, scary times. We're already seeing it with Antifa and the Antifa defenders.
Things are about to get real. Well, within the next 10 years or so.