I believe he means that, once the copyright on the code runs out (in 120 or whatever ridiculous number of years the copyright monopoly was able to extend furthe

I believe he means that, once the copyright on the code runs out (in 120 or whatever ridiculous number of years the copyright monopoly was able to extend further), that version, which is illegal right now (and not legally under the GPL) will automatically become GPL'd. This is an interesting take on copyright and licensing.