> US basically has a firearms license but by exclusion.

The essential quality of a license is that you have to affirmatively apply for it, so it operates by inclusion, not exclusion. You're like saying "We basically have an opt-in system, but it operates by opting out." I get your point that it has a similar effect, but words have meaning.

Yes of course. My point is we've gotten around the contentious aspects of calling it a 'license' by basically doing a similar thing but evading challenge by disqualifying anyone that wouldn't qualify for the 'license.' If you exclude everyone that wouldn't qualify for the 'inclusion' you can emulate a license with pretty good approximation.