"People get away with copyright infringement elsewhere all the time."
That doesn't make it right. Nor does it mean those those that call violators out on it should be chastised.
Ideally Oracle would change ZFS to a GPL-compatible license but I don't expect this to ever happen. The free world doesn't really look to Oracle for pro-freedom activities.
"Also, copyright doesn't lose force because some other case of infringement is occurring. Suppose Canonical is infringing the GNU GPL and nothing is done about it. Suppose they then infringe the GNU GPL in the same way, but with proprietary software. Someone wishing to take action against the latter case doesn't lose standing in court because he didn't take action in the former case."
I never said they did. The point that I was trying to make is that if this isn't a violation, then proprietary kernel modules aren't either.
"What's more, there's already a disconnect between at least the FSF's opinion on what the GPL permits and what the copyright holders of Linux allow to happen. Heck, what about proprietary drivers? I don't know much about Linux, but my understanding is ZFS is being used the same way proprietary drivers are, right? If I'm understanding this correctly, the thing being done with ZFS is already an established practice, the only difference here being that ZFS is not proprietary, just GPL-incompatible. So making a fuss about ZFS now is completely backwards."
Proprietary kernel modules are also a GPL violation so nothing's different: shipping zfs.ko is just as infringing as nvidia.ko was. In fact, please take note that they don't ship nvidia.ko because they were threatened with legal action in the mid-2000s. Canonical comparing zfs.ko to nvidia.ko was not a good idea, because they had effectively previously admitted that that was infringing. If your argument is that incorporating pre-compiled proprietary code is just fine with the GPL, your argument is bad.
"Do you honestly think that anyone would actually have an incentive to start suing small distributors of Ubuntu for whatever pennies of "damages" can be collected from them based on this?"
Proper GPL enforcement isn't about money but solely on achieving compliance. You should read up on https://sfconservancy.org/copyleft-compliance/principles.html
