People are indeed passionate about violation of their community values. Rather than coming from the rational mind, these are very much matters of the heart. So it is that rational strategy and closely-held values come in conflict here.
The problem with an alliance with PPs is that their form of non-monogamy grossly violates what I'll refer to as the spirit of polyamory ("SOP") as highly valued within the poly community itself. Note that there are many people practicing polyamory who are not denizens of the poly community - in some cases because they don't share the social POV that at least in part underpins the SOP.
I know of no organization that is in the process of forming an alliance with PPs. As a practical matter, the poly community supports no organization sufficiently to have influence over what any does. If Woodhull Freedom Foundation or
Whomever contemplates this approach would be well advised to both plan carefully how to explain the political expedience of it to feminist polys who highly value egalitarianism - and there are many, many of those – as well as be prepared to come under considerable criticism as they likely go it alone. Inclusiveness being also a closely held poly community value, that argument may persuade some - it would be interesting to see if it succeeded.
I'm not usually a skeptic, but on this question for purely pragmatic reasons I just don't see polyamory community support for an alliance with PPs happening anytime soon. The squick factor is just too significant. Perhaps an appeal to self-identified polys who live outside the poly community would get more traction.