I'd really like to agree with you, but I have long, long experience working with this issue due to working with OpenAFS (whose implementation predated the existence of Linux, although I suppose one can argue about whether the small amount of Linux-specific code is a derivative work). It's covered by the IBM Public License, which is another GPL-incompatible license (although for less significant reasons).

Our experience is that EXPORT_SYMBOL_GPL gets slapped on all sorts of things essentially at random, including interfaces for which you can't make any coherent claim that they're more of a copyright violation than many others not similarly tagged. Symbols that were available in previous versions are often withdrawn behind the EXPORT_SYMBOL_GPL barrier unless people complain (a lot), despite Linus's previous guarantee that this wouldn't be done. It's basically a complete mess from the perspective of a third-party, open-source kernel module developer (and relicensing OpenAFS is a giant disaster that won't ever happen, for reasons that aren't worth getting into).

The kernel definitely does not have clean hands here.