AFAIK they are saying that because it is a DKMS module and Linux is not a derivative work, they are not restricted from using it by the license. By Canonical's

AFAIK they are saying that because it is a DKMS module and Linux is not a derivative work, they are not restricted from using it by the license. By Canonical's interpretation, it would only become an issue if they were to build the support directly into the kernel natively rather than using a standalone zfs.ko file. Keep in mind IANAL and this is just my limited understanding of the issue.