I think you got downvoted because on face value that looks like a cheap shot. But in truth it does play well with Trump's fanbase when he takes aim at an opponent and starts talking smack about them publicly. Those opposed to Trump, it seems to me, tire easily of that and prefer a bit of civility, or at least the pretence of it.

So what you're saying is roughly "when you engage in petty slap-fights with Trump you kinda are playing to his strengths" - which is true.