Exactly. They're arguing the combined work clause, which would automatically rule out all binary-only modules, such as nvidia.ko.
Most previous arguments about zfs.ko were about the derived work clause, which is much more grey. I belive that nvidia.ko would be more likely to be ruled a derived work than ZFS.ko, but that's hard to tell.
It does seem silly to argue about ZFS in this context. ZFS is open source and much less offensive to kernel developers than nvidia.ko.[1]
If nvidia.ko is fine, then so is zfs.ko. If nvidia.ko isn't fine, zfs.ko may or may not be fine. Ubuntu has been shipping nvidia.ko for years.