Lets face it, Trump's base of supporters isn't really smart enough to talk about the real issues. They will eagerly swallow any bunk that Trump spews out, regardless of whether it would actually work, or whether it contradicts something Trump had previously said.
Maybe when dealing with Trump, petty might actually work. The racist Trump supporter (well, ok that is a bit redundant) isn't smart enough to understand "Oh, Trump is lying when he talks about republicans supporting health coverage for pre-existing conditions", but perhaps they may be smart enough to understand "The president's penis is small so he is not as manly as I want the president to be" or "The president is too dumb to operate an umbrella", and thus decide to not vote for him.