From the letter;

We call upon our community leaders to speak out against this protest and the potential harm it will bring to children both from the 2SLGBTQIA+ and Muslim communities, and the children who identify as being part of both communities.

[Emphasis mine]

Subtle, but it's there. To be clear, that phrasing leaves open the possibility that they don't actually accept their claims or identities as legitimate, but the modern use of "identify as" and similar constructs implies at least conditional acceptance of that claim.