Gagdad Bob over at One Cosmos has an absolutely brilliant analysis of what drives the left: envy. Riffing off the left's attacks on Flight 93, he really gets to the heart of it.
According to Webster's, envy is defined as "malice," and a "painful or resentful awareness of an advantage enjoyed by another, joined with a desire to possess the same advantage." The psychoanalytic understanding of envy is that it is an unconscious fantasy aimed at attacking, damaging, or destroying what is good, because of the intolerable feeling that one does not possess and control the object of goodness. As such, it is an aspect of what Freud called the death instinct, since it ultimately involves a destructive attack on the sources of life and goodness. Particularly envious individuals cannot tolerate the pain of not possessing and controlling the "good object," so they preemptively spoil it so that they don't have to bear the pain.
Which effectively explains the way they left is constantly tearing into what they disagree with. The frontal attacks on things that are really either objectively good or actually neutral but which the left dislikes are subjected to spoiling:
If you have an “ear” for envy, you will detect it everywhere in the liberal world. In psychoanalytic parlance, it is also called “spoiling,” or devaluing. Again, because the envious person cannot tolerate the good, he attacks the good and makes it bad. So even in my crappy little paper, The Los Angeles Daily News, they can’t help themselves (I long ago canceled the L.A. Times because of its unhinged leftist envy… I do miss the much higher quality, er, "intimate apparel" ads, though). For example, the headline regarding yesterday’s upbeat economic news was “Fed Chief Warns of Stagflation.” This is typical. One could be cynical and say that this is just “spin,” but I don’t think it’s generally conscious. Rather, I think it’s unconscious envy and spoiling.
It's a long piece, but it is truly devastating and well worth the read.