Your are correct. And my example of being certified by the State to use a crossbow for hunting vs. being certified by the Feds to own a scary AR pistol isn’t the best example. In my State being certified to use a crossbow is pretty easy. Just a doctors statement.I tried to explore this subject, with a member who is a retired Doctor. Wanting to gauge the willingness of Doctors to go up against the system, post ObamaCare and WhuFlu. From the Doctors response, and the pushback he received from other members, he realized that he was in the minority, and complained to the mods. Unfortunately that conversation has been removed.
The gist of his answers, were that he would tell us how the diagnosis/prescription could be worded, but would be unwilling to question the governments position.
In my experience lately, it would be pretty tough to get a Doctor to risk his livelihood, to help protect a constitutional right.
My comment tags off of the disabilities argument. A provision may be allowed, but being certified through that provision may be difficult if not impossible, as you pointed out.