I suspect that the primary reason for the dearth of Jewish books debunking Christian beliefs in Jesus is the same reason that there are not a lot of Jewish books debunking belief in Spiderman or Superman or the Green Lantern — such beliefs are self-evidently absurd.
If a non-Jew wants to bow down to a false god, we Jews aren’t going to waste our breath trying to talk him out of it.
According to a midrash, God chose Abraham because he intuited that there was one God who created and ruled the world and Abraham acted on his belief by destroying his father’s idols. Jews have inherited this orientation. For 4,000 years, we have been denying the validity of the false gods of the goyim. We do not do this primarily through writing books against the false gods of the goyim, but by living our lives in allegiance to the one true God of the universe who chose us to be His people.
I think this iconoclastic inclination is the reason that Jews account for most of the great stand-up comics in America. (Also, Jews tend be secure in themselves and have no problem making fun of themselves — as opposed to, for instance, Muslims who are always crying about dishonor. If you’re always worrying about dishonor, you’re probably not going to make many jokes in public about your group.)
