You know, I just realized something. Despite my admittedly snarky post, there have been times - one past, and one ongoing - where professionals have indeed assembled in order to provide support for the government narrative. Or to be more specific, in order to demonstrate acceptance of the NIST findings:
The first would have been the NIST request for comments meeting (meetings?). Yes, I know it's weird to consider something specifically held to critique NIST's draft reports to be an event supporting the dominant narrative, but think about it: The legitimate, professional organizations (like Arup, for example; they had representatives there) and individuals (like James Quintiere) had critiques that accepted the broad strokes of the NIST narrative, even though they differed with the finer detail. Hell, part of Quintiere's critique was that NIST didn't go far enough with some of their stuff. And the other is that different parts of the structure would've failed first. Both those accept the broad strokes narrative of jet impacts causing damage and fires. At any rate, those commenters may have been critiquing the NIST findings, but they weren't doing so in a way to invalidate them. Rather, they were challenging NIST to improve their report. A report that they agreed with in general, just differed with in specifics.
If those professionals didn't agree, they would have been calling for a redo themselves, and wouldn't just be critiquing individual points.
The second: The ICC meetings. That's a group of professionals who meet regularly (Every other year? Every 3? Something like that?) to consider proposed code modifications. Remember: The whole point behind the NIST investigation was to see if there was any way to prevent collapses like the Twin Towers and 7 World Trade. Specifically, they were studying the collapse in order to see if there were any modifications to practices necessary to prevent future tragedies. Practices which would be constrained and influenced by building regulations, which in turn are influenced by construction codes. The ICC meetings would be judging whether to add those modifications to code (and indeed, some of the minor recomendations have already been accepted), but they would be starting from the point of accepting that NIST's findings are legitimate enough to consider. So no, that's not overt advocacy of those findings, but it is support in a way because it's acceptance.
So in sum: Were there any professional groups that got together out of a sense of activism (like AE911T, for example) in order to support the NIST narrative? No, of course not. That would be not only be silly, it would be unnecessary because they have professional channels to express either support or dissent through. But have there been cases where those channels were used by groups of professionals to express support of NIST's basic findings, either via commentary on their report or consideration of applying them to practices? You bet.