> Judaism isn't Christianity any more than Islam is
All three share common beliefs and values. Christians and Jews worship the same God.
Islam IS closely related to Judaism and Christianity and the Quran explicitly states Muslims worship the same God.
> Trying to apply Christian norms to Jewish practices usually ends up in a pogrom when Christians realize that Judaism isn't Christianity.
BS. Thinking about where we agree and where we disagree leads to greater understanding. Pogroms are motivated by ethnic differences and othering people, not by theology, religious law, or anything thoughtful.
> I have no idea why the right in America has run with the whole "Judaeo-Christian Western Culture"
Is it a right wing concept? The term seems far more widely used to me than that. They see correct to me, because western culture (that of the left, as well as the right!) is a product of Christianity, which is an offshoot of Judaism, so you cannot ignore the Jewish influence.
> when Christianity was founded from the start on not being Judaism and making a clean break with it.
It was far from a clean break, and the intention was not a clean break. There was much argument (see Acts) in early Christianity about which Jewish practices to follow. Christians use Jewish scriptures and prayers and symbolism. The first Christians were Jews, and they would not even have considered themselves converts at that point, just those who followed the promised (to Jews!) messiah.
> You might as well say Cristiano-Islamic culture since there was about as much impact on Western thought by Islam as there was by Judaism.
Not true because Judaism and Christian culture had a greater and longer lasting history of geographical and cultural overlap than Christianity and Islam.
On the other hand, all three religions have a lot in common.