Yeah, I think it's fair to say that drag is a distinct form of crossdressing and also represents a departure from gender normative behavior, so I could see there being a forum for it.
The question is whether such a forum would ever be used. As I brought up regarding the lack of a specifically female crossdressing forum, if a group is reasonably accepted, it's unlikely they'd come here looking for support. Drag queens (and kings) are accepted as dressing according to the gender that matches their body and identity most of the time and when they're in drag, it's usually in a supportive environment, whereas crossdressers usually want to exist in their day-to-day lives dressing as a different gender than their bodies and identities, which comes with a whole different social stigma.