Jewish cursing of Jewish Christian converts? Something not heard of lately

Interesting essay where the issue of Jews cursing Jews who become christians is taken.

I suggest that we need to address this evidence with immense caution, admitting that while it is abundantly clear that the birkat haminim eventually was, in its medieval forms, a curse of Christians, we simply cannot document this in the period of its putative origins in the late first or early second century CE. It therefore cannot be identified with any certainty as a player in the “partings of the ways,” although it certainly served later to reinforce the boundary between the two communities.

Have a read of the whole essay.