What drives, as it’s now generally referred to, Trump derangement syndrome? My two cents - leftists are idealists, to put it gently, delusional fantasists to be a bit harsher. Ultimately everything idealists believe is founded upon an illusion and then assumptions built up around that illusion in order to make it seem real. Take the now fallen out of favor attempts to prove the existence of God - for the idea of God to make any sense, he had to be ‘perfect’ - anyone seeking to prove his existence needed to start with that - and therefore start with the illusion that it’s possible to know what perfection is - an illusion fed by a wish - the wish being, I need for there to be a God who is good.
In a sense Obama was a progressive god - he often spoke of himself in those terms, progressives often [always] saw him in those terms - he embodied everything the left wants to believe is true about themselves and the universe they inhabit - he had to be perfect otherwise that god makes no sense - he therefore also had to be an illusion held aloft by assumptions because idealist systems cannot abide imperfection and still function - absolutist systems are dependent on the illusion of perfection absolutely. This is why the left simply cannot get its head around the idea that Obama was not a good president - out of necessity, in order to maintain the illusion, the thought must be inconceivable.
Trump drives the left crazy because he is so unlike Obama - and if Obama for the left is the perfect embodiment of the ‘good’ then Trump necessarily must be evil - has to be otherwise the godhead makes no sense. Which leads naturally to the other reason they hate Trump - hate him as if he represents an existential threat - what if he’s successful? What happens to their belief system, their worldview, the very idea of themselves if somone who they necessarily view as evil succeeds? They treat him as an existential threat because to them he is - if he succeeds the perfect illusion of their idealism and therefore the assumptions that gird it up will turn to dust.
Or something like that. One can come at Trump derangement syndrome from several different angles. One thing for sure though - it’s telling us something about the liberal hive mind that scares the shit out of me a hell of lot more than Trump does.