Well you can read the thread on the mailing list but to put it bluntly - because they wanted to stop ZoL from working. They view non-GPL kernel modules as a violation of the GPL.

"My tolerance for ZFS is pretty non-existant" Greg Kroah-Hartman

"please switch to FreeBSD instead of advocating to violate the copyright and licensing rule on my and others work." Christoph Hellwig

For context, Hellwig is the guy that tried to sue vmware in Germany and had the case dismissed because the evidence submitted summed up to references of stuff on the internet and basically copy and pasted git output. It didn't even include details on which lines of code were allegedly used by vmware, or details on authorship in any of the code comparisons that were present.

Which is a shame, because it would have been nice to see if the shim usage pattern is actually a violation of the GPL - a lot of us would like a clear ruling there. I'm sympathetic to his viewpoint, but that whole ordeal was a bit of a "wtf?" because of how it was handled, and I can't imagine him being sympathetic to anything else in an even somewhat similar situation.

AFAIK, the VMware stuff is beyond shim usage. They straight up replace the kernel and run GPLed drivers inside their kernel.

> They view non-GPL kernel modules as a violation of the GPL.

But then why allow them?

users demand it. If the kernel devs pushed too hard legally a lot of users would switch to BSD (probably freebsd, but there are other good candidates). Linux is slightly better for desktop users, but if you cannot use your graphics hardware for legal reasons BSD will still work and is the lesser evil.

So basically NVIDIA gets a monopoly on the ability to release non-GPL linux kernel modules so that Linux can have a better reputation among desktop users (which is only a small fraction of Linux use in the first place)?

I don't get it -- do they care more about what the users want, or about enforcing copyleft? If it's the latter, then they should be happy if those users who don't care about the GPL move to BSD. If it's the former then they should stop playing games and implement a fair policy for all non-GPL module authors.

they is several thousand people with different motivations and desires. To expect them all to have a common motive would be a mistake.

People not associated with the leadership of the project shouldn't be making decisions about what licensing models are acceptable or not in the first place.

Because the kernel dev decided that interfacing with the kernel through the API would change the kernel too much to not be in compliance with the GPL if your license isnt.

Its not non-GPL. Its non-GPl-compatible.

Which is proooobably a lie. It's pretty hard to imagine how such a generic function as enabling and disabling the fpu could mean that you're combining the two works. But there's not much process to call someone on technically inappropriate use of _GPL. It's a mostly-political tool pretending to be a technical tool.