But religious Jews think that Christianity, the Trinity, Jesus Son of God and God incarnate, is an appallingly blasphemous heresy, and those words are too weak to describe it. Non-religious Jews will tolerate each other pursuing atheism, trans-humanism, Shamanism, Buddhism, but not Christianity - the line which cannot be crossed.
You might consider yourself a Jew, grafted to the tree, and while some Jews appreciate your support, I doubt you will find Jews who think you are a Jew.
My allegiance is to G-d and His promise. The inability of some Jews to accept me as a member of the Chosen People is of vastly less concern to me than that G-d accept me as such.