And as noted in the first page, in an indeterminate number of states , the accepted training is open ended enough to be essentially none.
And between all three catagories the rates of accidental and mistaken shootings are equally near zero. And it's not as if LE and Mil don't have slip ups.
I'm a firm believer in knokledge and useful skills. My personal belief is what a reasonable and competant person should know and be capable is quite high. But even if mandatory training were Constitutionally viable , there is no statiscal need.
Many Gov'ts primarily seek as many roadblocks as possable to discourage people from carrying. ( Even if the actual training is basic there is the hassle of getting a training slot from an Offical State Certified Instructor , fitting into one's schedule , traveling to their location , and of course the $ ). And among a certain % of Official State Certified Instructors, they will be in favor of having a captive audience for their services.
Yes , many of the Instructors are good people , and can even teach useful skills. Such Instructor should have no trouble having clients who volentarily wish to train with them.