He is not saying Trump is worse than Hitler. He is saying that comparing people to Hitler makes light of what Hitler did. But the title is salacious and misleading. Probably the editor’s idea.
What he is saying is that Hitler was a demagogue who rose to power playing on the worst elements of his society, but did so because he believed in something. Trump is pursuing power, exploiting the worst elements in his society, but for no reason at all other than self aggrandizement.
Or more directly, Trump is asking the irredeemable and deplorable to support his candidacy to help him sell books, to start a cable news network, and to steal money from his campaign by overcharging for hotel rooms his staffers use.
This is what the author says, not my opinion at all. I grow very tired of armchair psychology very quickly. Nobody really knows what drives or motivates other people’s decisions. We only have their actions to judge them by.