It is a curious psychological phenomenon, but hardly anything new. Villains have also been heroes since times immemorial.
People play out their darkest fantasies through proxy, whether they're aware of it or not. Even revulsion, if obsessively pursued, is often a repressed wish fulfillment fantasy.
Humans are a complex animal, sometimes quite nasty. Ever seen an angry Chimpanzee? And they are pacifists compared to homo sapiens in its natural habitat of roaming hordes and tribal warfare. Utopians dreaming of a world without hate and violence negate the very basic human nature - we are apex predators with warfare and intra-species rivalry as the primary means of population control and natural selection. We are what we are. Instead of repressing this we should channel those instincts into something beneficial or at least harmless. Sports, video games, arts, fair merit-based competition of any kind. Civilization is all about harnessing and channeling the darker side of humanity to better ends.