I think this mostly comes down to (1) people are more aware of Nazi Germany and thus its easier to use that context than another and (2) the Nazis were extreme even by comparison to their contemporaries and thus have been (presumably) studied the most.
Yeah, but it breaks down because Trump also knows that history, and knows that people want to compare him to Hitler, so he does a bunch of things that make the comparison harder.
Trump says things like "there's no greater friend to Israel than me" and "I'm the best president for black people". One of his most viscerally anti-immigrant lackeys (Stephen Miller) is Jewish.
Trump’s choice of "illegals" as the cause of America's woes is smart, because (1) they can’t vote and (2) even American-born children of undocumented immigrants hear that and think "oh but he's not talking about us". He was careful to not say "Latino immigrants", even though that's what a lot of his white supporters heard.
The actions are right out of Hitlers playbook. Find a group or groups, to blame and demonise, that are powerless. Deflect and encourage the wider populations grievances and dissatisfaction onto them to provide a common enemy and warning to others that they could be next if they don't join in. That together with establishing a cult and encouraging extremes echos the establishment of the Natzi party surely?
