If it is a joke, it is just as bad because then it sounds like he is mocking his supporters.
A bit of an intellectual exercise.
Pretend you are a to Democrat strategist. Pretend that you are facing a campaign with probably your worst candidate in decades. Also pretend that you have a goal of delivering a knock out blow to the Republican party- to permanently divide them helping guarantee you an election with your weak candidate but also divide your opponents to obscurity. Write a strategy plan for that, the best one you can come up with.
Now look back at that strategy plan and ask yourself how much different that is than what Trump is doing.