Its because of the expectation of privacy. They think they know that anyone who would make a gun this way wants to do it in a way that keeps their privacy.

That is the issue they have.

Gun shows and stuff sure they know about that but they have tons of feds play dress up like normal people and go to those to phish for info. If they really want to they would check all the cameras which I would bet gold they 100% do.

But this is made for privacy and that’s why they view it as a problem.