Matthew and the parting of the ways

Anders Runesson's essay, "From Where? To What? Common Judaism, Pharisees, and the Changing Socioreligious Location of the Matthean Community" (Common Judaism: Explorations in Second-Temple Judaism, edited by Wayne O. McCready and Adele Reinhartz [Minneapolis: Fortress Press, 2008], 97–113), is as awkward as its title. I think I'm sympathetic to his overall thesis, but it isn't easy to tell.

But his final paragraph uses a familiar phrase in a peculiar way:

In conclusion, the Gospel of Matthew provides us with early evidence of an inner-Jewish parting of the ways, very different in character from the process that much later would lead to the establishment of "Christianity" as a religion independent of "Judaism." Indeed, the use of the Gospel of Matthew by non-Jewish Christ-believers as a resource in that later process of identity formation is a fascinating and hermeneutically complex problem that deserves further study. (113)

My question: How helpful is it to refer to "an inner-Jewish parting of the ways"? The point is clear enough: the Matthean community (if we can still speak of a "Matthean community") split from a[nother] Jewish group rather than from Judaism itself. But the metaphor parting of the ways has been used historically to refer to the differentiation and dis-identification of Jewish ways of being from their Christian counterparts, and vice versa. If Matthew presents evidence of and for continued Jewish identities for those who found their traditions in its telling of Jesus' story, shouldn't we jettison parting of the ways language tout court?