There is a bunch of explanations and legal opinions here.
Oh? And let me tell you there is more than a boat load of lawyers who disagree.
See the links on page you linked to (!): http://www.networkworld.com/article/2301697/smb/encouraging-...
> There is a bunch of explanations and legal opinions here.
Did you read the text of that page or any of the linked articles? The OpenZFS position is clear: "However, there is nothing in either license that prevents distributing it in the form of a binary module or in the form of source code."
I guess that alone could be enough to come to the conclusion that it is not worth the trouble.
Linux had ~5 years to try and add ZFS before it was bought by Oracle, and did not do so. As much as Oracle is often the villain, I don't think they're what the Linux team fears here.