Any criticisms of Trump's behavior really just come down to him not being the standard "good loser" Republican we've been conditioned into thinking of as the Proper Conservative Politician. I would imagine that the process of selling us the image of what a politician should be probably started with the development of photography being easily reproduced in newspapers, and certainly ramped up with the advent of television. The idea of a very proper politician, straight-backed and always attired in a suit with a look of solemn determination on their face has been shilled to us so much that some particularly easy to manipulate people are just straight-up disturbed by a failure to adhere to it.
(Amusingly this doesn't seem to apply to female politicians, who can do whatever the fuck they want and not be held to the same standard. Sexism of low expectations strikes again. But anyway.)
Reminds me of a comment thread once where some Very Proper Republican had himself a case of the vapors over Dubya inviting Kid Rock to play at an inauguration party. He wanted brass bands playing nothing but century-old songs, and when pressed explicitly said that yes, an inauguration should absolutely be boring because that is adult. Besides that indicating how sad and boring his adult life has been, it's such a bloody consoomer point of view, because he and people like him have internalized the branded and focus group refined image of what a politician is supposed to be and what political events are supposed to be like until they can't see someone who deviates from that without clutching their pearls.
Meanwhile, you know what attracts people who are tired of being bored? Things that are different. Things that aren't the standard. Hell look at those ugly-ass Cube cars... they're unaesthetic as fuck, and yet when they came out and for years after they sold off the lots as soon as they came in. Why? Were people that desperate for a high ceiling in their trunk space? No, they were different. They didn't look like anything else on the road. They were distinct from the painfully same-y four door sedans and SUVs that the car companies were cranking out. People get sick of the standard and they want to try something different. Trump, as opposed to the pugugly Cubes, has turned out to not only be different but beneficial. If that's at the cost of the image of a Proper Politician, good, shoot the image in the head and bury it in a landfill.
Only an idiot would rather have a good loser who acts like a gentleman over an effective bastard.