My Theory

Well The Left can't deal with reality because in reality they're the bad guys.  They're constantly trying to live off the work of others thus they have to control their "livestock" by force.  Since reason tells us that such behavior is morally intolerable they"re left with emotional whining as their means of justifying their actions and allowing themselves to feel good about it.  Any refusal to accept the emotional bullshit and obey the self-appointed masters is automatically translated on the emotional level as something to the effect of "die motherfucker!"

That's my theory, anyway.