It wasn't Glock being dense, I'd bet my NFA fund it was some PD, medium to large sized, and either Californian, or NE costal, that made a mention of being worried about it. Probably some blather about "Criminals practicing disarming techniques" or whatever, as if they couldn't do it with toy guns, Airsoft or any number of things (unloaded real guns) just as easily. But Glock and the BlueGuns company was more than happy to comply considering that LEA's are still likely to be 99% of their business.
Of course in reality it's just about "protecting the talismans of the tribe". We've got special cop-stuf that makes us feel... special. And other people shouldn't be able to have it.
There's plenty of this attitude in any number of industries, not just law enforcement supplies.