I believe that had been the case for some time, but it will no longer be true with the next Ubuntu release. (that is why everyone is particularly concerned about the issue right now)
If you look at the .diff.gz associated with Xenial's kernel, linked from http://packages.ubuntu.com/xenial/linux-image-4.4.0-7-generi... you will see that this diff adds spl/ and zfs/ directories to the linux source tree. I believe, but don't know for certain because the "[list of files]" links are all broken at the time I write this message, that zfs.ko is in the same binary .deb package as the GPL'd kernel.
That's not to say that mere aggregation is enough to trigger the portions of the GPL that also require a derived work in the copyright sense, but the Conservancy post we started with lays out in detail their view: A particular zfs.ko does nothing until it is linked with a matching version of the Linux kernel; the fact that the linking is dynamic and not static is irrelevant in their analysis.
