I find it odd that the core of Judaism still seems to revolve around the rejection of Christ. Why do they give Jesus all that power? Why don’t they just go about their business and worship their God? I don’t believe in Buddha, but the rejection of him isn’t the center of my beliefs. Hmm… is there something deeper? Makes me wonder…
Actually, our CORE has nothing to do with Jesus. Jesus was a nice Jewish man, but he is pretty irrelevant to Jewish teachings. The CORE of Judaism is obedience. Consider that in the Tanakh, the word "law" is written about 200 times. Compare this to the word faith, which appears only 50 times, or belief, which is even more rare.
Traditionally, any Jew who converts to any foreign religion, whether it is Christianity, Hinduism, or Islam, is considered apostate.
However, it is true that conversion to Christianity is treated with extra hostility. This is because for the last 2000 years, Jews have suffered forced conversions, harassment, persecution, and even death at the hands of Christians. No other group has sought to harm us over such a long period of time or to this degree. I've met Jews who tell me stories of their Zayde being a child and hiding in the cupboard while Cossacks wearing crosses and shouting "Christ Killer!" have murdered their parents. Keep in mind that Hitler made use of Christian antisemitism, and that in fact most Nazis were Christians. For these reasons, a Jew who converts to the religion of our persecutors is rather seen as a traitor to his people.
I fully acknowledge that most (not all) Christians reformed from this after the holocaust. But historically, antisemitism has come in waves. Just because things have been pretty good recently doesn't mean the tables won't turn again. IOW it will take more than 80 good years to gain our trust back.
And honestly, given the attacks on Jews and synagogues today, it looks like the pendulum is indeed swinging back to persecution.