They sound very confused. Liberalism will get Israel destroyed.
You're right. Liberalism is based on subjectivism and moral relativism. They think that, since they believe religions are all man-made arbitrary nonsense, and that morality is taught by religions with which they disagree (including their own in many cases), that therefore ALL morality is just arbitrary nonsense. It never occurs to them that REALITY also dictates being able to distinguish right from wrong. So to them, uncertainty is a badge of honor, and certainty is a sign of hubris and evil. Naturally, this is the philosophy of a "shmoo," the creatures in the old Lil' Abner comic strip who jumped right into frying pans and begged to be eaten.
Ironically, some of the most rational, pro-America, pro-Israel intellectuals have been highly-focused, thinking Jews (Ayn Rand was just one example) who condemn the self-righteous amorality and defiantly bellicose uncertainty of moral relativists in general, and liberals in particular.