Being pro-Palestinian is essentially shorthand for subscribing to the constellation of beliefs that define liberalism; i.e. identity politics, multiculturalism, and relativistic moral beliefs.

I'd like for you to imagine a perfectly rational, dispassionate observer. Picture an observer who is totally uninfluenced by modern political considerations; an observer whose only frame of reference is clear-minded morality.

Now, imagine this hypothetical observer learning of the facts surrounding the current conflict between Israel and Hamas. Hamas routinely fires indiscriminately into civilian areas, yet Israel is more widely condemned. Hamas intentionally mixes in with civilian populations, yet Israel is defamed for the unavoidable collateral damage incumbent in protecting its citizens. Israel refrains from totally leveling Gaza, at great personal cost, yet the nation is excoriated for disproportionality. This despite the fact that Hamas has shown no compunction about using the citizens they claim to be defending as homicide bombers. We all know exactly how our observer would react: with complete disbelief.

So, how best to explain such a systematic failure of moral logic on the Left? It's tempting to assign it all to stupidity and/or amorality, but I would wager it is merely one symptom of an inherit flaw in liberal thinking. And to root out this flaw, we have to look at nineteenth century German thought.

While not an integral philosopher for most on the Right, Frederick Nietzsche is indisputably one of the most important thinkers in modern history. His influence on moral thinking is huge. Nietzsche, perhaps the most eloquent proponent of nihilism, argued vehemently against moral systems in all their forms, particularly Judeo-Christian ethical systems.

While the familial likeness between his position on ethics and modern schemes of moral thought on the Left are self-evident, what may not be readily apparent is Nietzsche's bifurcation of morality into Master Morality and Slave Morality and how this serves as a catalyst for the Left's demonization of Israel.

Nietzsche cast Master Morality as the morality of action, of strength and self-possession. Master Morality deems moral "good" as being synonymous with what is useful or helpful. Slave Morality originates out of weakness, and is the morality of the self-identified "oppressed." Slave Morality identifies "good" with whatever is in opposition to Master Morality. As a result of this oppositional bias, moral reasoning is divorced from any consideration of the world in-and-of-itself and is instead solely subjective. Our hypothetical observer would recognize this oppositional bias vis-a-vis the current debate concerning Israel and Hamas. 

When Nietzsche made this observation he applied it to the contrasting moralities of the Roman Empire (Master Morality) and the Jewish and Christian minorities (Slave Morality) in their midst, which eventually won what amounted to a kulturkampf. The modern Left has preserved Nietzsche's dichotomy, but reassigned the roles, making anything Western, particularly American and Israeli, and anything religious, especially Judeo-Christian religion, the Master. 

Looked at in this light, liberal opposition to any attempt by Israel to defend itself immediately makes sense. Israel is not roundly condemned because of its reaction to the facts as they exist – how could they be considering how lopsided things are in their favor – but because of who they are. Israel is strong. Israel is the only Western-style democracy in that region of the world (though I have faith Afghanistan and Iraq will join the list in due time). Israel is a proud bearer of Judeo-Christian culture, and a staunch American ally to boot. Israel, in liberal eyes, is the Master.

So in effect, Israel becomes a shibboleth, a password by which one signals his or her empathy with the oppressed, the underdog, and the losers in the lottery of life. Being pro-Palestinian is essentially shorthand for subscribing to the constellation of beliefs that define liberalism; i.e. identity politics, multiculturalism, moral beliefs that, if not de jure relativistic, are so fraught with exceptions, equivocations and subjectivity as to be de facto relativistic.

Hence, the Left's view of Israel is unthinking. It is not the result of deliberation, but is merely a semaphore flag, a banner with which to identify yourself. 

But let me not be misunderstood. I, nor most folks on the Right, advocate Master Morality. In fact, the idea of the Ubermensch and all the evil implicit in the concept bears partial blame for the rise of Nazism. However, such a view is affixed to the conservative movement by the American Left, and this explains the indefensible conflation of Israel and Nazi Germany that has been on display during the recent demonstrations against Israel. We must be cognizant of the philosophical foundations of those aligned against us so we can prevent playing the role they have scripted for us.