"What I dont understand in this day and age, why there are any liberal jews?" Because they live in communities where they hear nothing else? Remember that famous story about a New Yorker who asked how Nixon could have won when she didn't know anyone who voted for him? Could be someone from the family my daughter married into in Queens, I see them on holidays in Boca Raton. One had never met a Catholic, and was leary when she learned I am one. Her husband is a professor.. It is the same in parts of LA.
There's also inertia, and cognitive dissonance. Dems make enough friendly staements about Israel to trick Jews into believing the Dem Party is a friend to Israel. There is also the concern about Christian antisemitism. The prominence of Christians in the Rep Party may also intimidate Jews, even though conservative Christians are extrememly supportive of Israel. People's childhood memories linger.
I was talking to a guy I know, who mentioned being beat up for being Jewish as a kid. He's supportive of Bush (WoT)& Israel, but I'm sure there are many Jews who are apprehensive of Christians.