Plus, when do you freeze truth and say that is how it should be.

Again, good points.  Kabuki is currently and for most of its history has been an all-male form of theatre.  However, its founder was a woman and originally women played both male and female parts.  So which is the "real" kabuki?

Equally in a world where artistic, cultural and gender boundaries are being challenged it seems perverse in the extreme to declare that some things just are and that we can't tinker at the boundaries.

As I wrote in my previous comment, I don't think (though I don't know for sure) that she believes racial and cultural boundaries "just are" and goes by some kind of yes-no black-white check-list.  I am sure she considers each case on its own grounds within its own context, and looking at the unique pluses and minuses that each case may bring to the community, aware that no pre-formulated definition or check-list can exhaust the unanticipated possibilities that reality may bring up.  At least, I hope and expect she does.

An excuse for darker inadmissable reasons.

I am unclear as to what you imagine these reasons may be in this particular case.  What is real -- based on what I have seen personally -- is that her dance group provides a very meaningful and fruitful experience, artistically and "personally", for its participants and audience, and the bathwater must be really really dirty in order to justify throwing out the baby (the "women of color" membership requirement) along with it.

Truth unfolds in time through a communal process.