The PRC was allowed into the WTO on December 11th, 2001. Under the TRIPS Agreement, computer programs are protected as literary works, and per that same agreement, the general term of protection is 50 years and shorter terms may not be applied. There’s some stuff in there too about the life of the author, but basic no frills copyright: no fewer than 50 years. The first works covered by the GPL are not yet that old.

Yeah, the PRC is basically disregarding that, and yes, the Courts of WTO members are empowered under the TRIPS agreement to provide relief to the copyright holders. Start with Article 42 and work your way up. Chinese law doesn’t even enter into it, and under their political system, is explicitly “rules for thee but not for me” given that the CCP sits above the government and the law.

After they export their products to countries that honor the GPL, does Chinese law matter?

I would be surprised if China was not a signatory od the international copyright law agreements: without that, works coming out of China would arguably be unprotected in the rest of the world too.

As such, even if there might specific incompatible provisions in GPL, the nature of the license should be enforceable only if they cared.

Though, to be honest, even in US and the "West", we haven't seen many cases where non-copyright-owner was able to score many GPL wins.

The core copyright law is not a western thing - while it's not completely universal, the Berne convention harmonizes it to almost all countries in the world, see map at https://en.wikipedia.org/wiki/Berne_Convention#/media/File:B... . It doesn't apply in Iran and Somalia, for example, but in does apply in all the economies from China to Chile, even in North Korea.

I have no idea if they are legally in the right to not honor the GPL under Chinese law. But that doesn't matter. What they are doing is morally repugnant regardless of legality.