"BTW, I've been writing GPL'ed code for more than 35 years, and for the last 25+ years, it has been my full-time self-employed means of making a living."

That is embarassing for such a self professed domain expert to say something as ridiculous as:

"You cannot (re)use any GPL code unless you agree to license your own code under the GPL."

I still don't hear an argument that actually shows how it's not a commons. If you're just arbitrarily declaring it actually means "public domain" I say you don't get to declare that and inventing your own definitions for terms is not a valid argument or even valid comminication, and there is no further point in attempting to communicate with anyone doing that.