This is just another example of a phenomenon that goes back literally centuries. Those on the left tend overwhelmingly to be believers in what Thomas Sowell calls "the unconstrained vision" of human nature, while conservatives and libertarians tend be be believers in what he calls "the constrained vision." And going back at least to the time of the French Revolution (and very likely earlier) you see over and over and over that believers in the constrained vision disagree with believers in the unconstrained, while believers in the unconstrained vision often HATE believers in the constrained. Believers in the constrained vision regard their ideological adversaries as mistaken, but very often still see them as well-intentioned. Believers in the unconstrained vision, on the other hand, very frequently regard their ideological opponents as moral defectives, who if they are not callous or indifferent to the unconstrained believers' cherished identity group (the poor, minorities, et al.), actively conspire to victimize them. Now, in Obama's case, factor in race -- bearing in mind that many leftists today are so indoctrinated in identity politics, that the race has precisely the same effect on them that the sound of a bell had on Pavlov's dogs -- and they become hate-filled, bile-spewing caricatures of humanity, seemingly INCAPABLE of reasonable thought.
As wearisome as all this is, it doesn't surprise me in the slightest.