That can't be a serious question. To run against someone you have to draw a contrast, say why you should be president and they shouldn't. You're explicitly splitting the party into two camps, yours and the incumbents, thereby turning part of your party's base against the incumbent.

Granted, in this specific case this complete clown won't get any real support but if it were a real candidate like Newsom over the course of a campaign there would absolutely be a contingent of people who become intractable and were "Newsom or bust".