What is this insane logic?
If someone modifies my code and doesn't give it to me, it doesn't deplete me of anything. For that to be true I would have to lose something I already possessed.
You maybe meant "deprive," but at no time did I ever have a right to anything that they created. It seems you're asserting that because they used my code I suddenly should have a right to use their modifications. I think that logic is flawed.
I do believe I should have a right to use anything I've created [1]. And if someone feels they've made changes that would be generally useful, and submits code to add to the code I've released, then I would be thankful.
But I wouldn't feel that I had the right to something created by someone else just because I gave them a gift that didn't even cost me anything to give them (aside from possible opportunity costs).
That's not to say that GPLv2 isn't useful for dual-licensing situations (like Qt), so as to convince companies to pay for full commercial use. But the latter situation does NOT guarantee user freedom (people will only pay if they AREN'T willing to release code, after all), and the pro-GPL arguments on this article seem to focus on user freedom, so you can't really have it both ways.
[1] I would love to see a programmer's bill-of-rights that guaranteed a developer the ability to reuse any code that they'd ever written that didn't include any actual business or trade secrets. I once wrote an awesome string class for one employer that was even actually open source, but that was licensed in such an annoying proprietary manner that, even though I can still legally have and use the source code, I can never redistribute the source code. The company made games, so there was nothing at all about the string class that anyone would ever have cared about in a business sense.