It's always good to consider the source of an argument, but it's an ad hominem fallacy to dismiss an argument on that basis. Sure, that might explain WHY he takes the position he does, but it doesn't address his argument itself.
He has been a gangsterment grifter his whole career, as you pointed out, so of course he's going to support the gangsterment. But the Founders had just spent a few years establishing a new gangsterment by the time the Second Amendment was adopted, so how likely is it that they would write something into the Constitution that could be the means of its undoing? Indeed, they made it very difficult to amend the Constitution, especially via a concon (constitutional convention, for the folks in Rio Linda). Once a State is created, it's prime directive is to preserve itself, even if that is against "The People" it was ostensibly created to serve.
I agree that a concon with Leftists could be a disaster resulting in a far worse gangsterment than we have now. That's why I favor Human Governance 3.0™ 😁
https://open.substack.com/pub/christophercook/p/era-democracy-must-end
It's not an ad hominem to dismiss his argument due to conflict of interest: in his lifetime, the Education Industrial Complex is as dependent on absolute power of its source of funds as the Military Industrial one is.
The founders made their constitution rather easy to ignore through "unconstitutional" statutes for which they expressly gave themselves immunity in their constitution, and through judicial activism that began during their lifetime under Marshall.
They began ignoring the constitution through statutes themselves: their Sedition Act for example, confirmed their previous Independence Declaration to have been a criminal conspiracy it was.
It's fundamentally absurd to pretend that "A Nation of Laws", based on the best constitution ever devised could result from an armed criminal conspiracy.
Just that fact, makes the whole discussion of what that gang meant in their " Amendments" pointless.
Their constitution was just a fig leaf to justify continuing the scam with taxing power The Confederation Articles didn't give them.
It was a fraud it's turned out to be from the beginning. If their constitution did actually create a government of expressed, limited powers, no Bill of Rights was necessary at all, much less their 2A.
Dismissing his argument because of a conflict of interest still evades tackling what he said on its merits.
But I essentially agree with the rest of what you wrote.
That whole argument about how many angels can dance on the head of a pin, is based on the premise that it's turtles all the way down.
He, like its founders, is expanding the argument, because of an interest conflict.
An argument based on false premises, has false merits.