Just a reminder that it's only "illicit" in theory, until that has been proven in court. What they're talking about is essentially a DRM within the kernel code that tries to prevent a loadable kernel module from guessing where the kernel data structures are in memory. They know that people are likely to push the envelope, and they're trying to make it as hard as possible as a deterrent. However you could argue that ALL closed-source loadable kernel modules are violating the GPL equally, with or without a "shim", and people have argued that, but we've mostly forgotten about it and use this DRM fiction as a stand-in for legal fiction. Or perhaps the GPL-tagged functions within the kernel count as an "API" in the Google vs Oracle sense and none of this matters.