They didn't dislike him before 2016 because he was one of them, he went to their parties, donated their favorite people lots of money, and did TV interviews repeating all of their talking points.
Trump is absolutely nothing like Hitler- Hitler was a completely sincere true believer in his cause, solidified his views clearly before he had any fame or power and stuck to them consistently, and was himself willing to die for the cause of blaming all problems on people different than him. Trump switches stories and allegiances like an 8 year old girl trying on princess outfits until one 'clicks' and gets attention- and doesn't care if the one he ends up with is left right or center- he tried them all.
Both your "cheap virtue signalling by the laptop class" and Trump have an identical underlying strategy and postmodern world view that things like integrity, principles, and ideals are for suckers, and the only thing that matters is constructing a narrative that gives you the most power and attention right now: e.g. fakery.
Both are even using the same basic absurd narrative that some evil outgroup that deserves to be dehumanized is causing all of your problems, and supporting authoritarianism with them in power will solve it- just different outgroups but both chosen strategically by the same process.
There hasn't been any president during my lifetime that didn't have narcissistic personality traits and strategies, but I am not 100% sure all of them definitely had full blown NPD, I'm not a psychiatrist. It's a disability than harms the person affected more than anyone else- people with it are very alone as they make no real friendships or connections with people, and are not capable of improving their life through self reflection and self criticism. They can be very successful but won't ever enjoy it- they will still just be terrified and anxious about their facade collapsing. It is a disorder where fakery is the very core of every action.