I think you'll find that is a terrible argument and isn't going to achieve your desired result. I personally use Free as in Freedom software. Which of course, doesn't require that it be free as in price, but usually is. So right now I'm sitting on probably millions of man hours of developer work and it hasn't personally cost me anything.

The problem isn't that I'm not willing to pay for software, in fact, I definitely am. It's just that I don't need to. Which is apparently the same for icons, since there are GPL licensed alternatives out there.

The irony of course is that I would rather pay for software released under the GPL then pay for a closed piece of software. But, by virtue of it being under the GPL, I probably don't need to pay for it.

Not when an equivalent free option is available.