I would change tacks in the discussion with people. Sure, in a perfect world, one would want everyone trained and competent etc, we surely want this to be the case of everyone who shoots near us at the range. But, we don't want to make exercise of a fundamental right subject to some government test where they could move the goalposts at will to deprive us of our rights (like the old "intelligence tests" that were required in the Jim Crow era to vote, intended to deprive blacks of the right to vote.)
If I happen to be around when this issue comes up in a discussion on CCW, I try to shift the discussion as follows. To the uneducated, untrained people = lots of gun accidents and bad stuff. Sure. But we don't want to go down the road of passing a govt test to exercise your rights.
Point out that a license to carry a concealed firearm is simply that, and no more. It is NOT in any state I know of, a license to USE the gun. Any use of a gun, even simply withdrawing the weapon from its holster, exposes the gun owner to police investigation for criminal violations. ANY time a gun comes out, the gun owner is accountable to the police and the justice system. What this means is that any untrained or foolish gun owner's CCW experience is bound to be a short one; do something illegal or dangerous, and you'll quickly find yourself with a revoked CWP and the issue is fixed, plus whatever penalties the law might bring down on you.
So, certainly, EVERYONE carrying a gun should be trained in safe and proper firearm use, as well as the law and the correct way to approach use of a gun. But, the best mechanism for ensuring this is the one I just described, don't mandate "competence" because that's wide open to .gov abuse. Having CCWers accountable for their actions is the best way to assure that people carrying can handle the responsibility.
I also point out that making some sort of competence mandatory isn't going to do squat to the bad guys who illegally carry anyway.