This is kinda obvious, lefts easily accept progressives guidelines, like immigration, multiculturalism, miscegenation, abortion, LGBT+, BLM, drugs release, anti traditional to pro scientific, atheism, feminism and transgender cause. This is all Jews want, to weaken the West, morally, physically and spiritually, making the population into a mass that is easy to manipulate. Directly the answer is this, simple and direct, the fall of the West is more important than support for Israel.