Earlier quoted context omitted.
ZFS on OSX was doomed the moment Oracle bought Sun. If you want to know why, just contemplate the smoking wreckage of the Oracle/Google Java API lawsuit.
ZFS is on a completely open source license. Oracle's beef with Google comes from actions that occurred before Java was open sourced. It's hard to see how the two scenarios are even remotely related, other than "Oracle"
Oracle's viewpoint on what patents are and are not granted by that license is also interesting (as was Sun's).
Interesting enough that Apple felt they needed to go get a patent license for it, and couldn't come to terms.
http://arstechnica.com/apple/2009/10/apple-abandons-zfs-on-m...
You are correct this happened pre-oracle, but note that it was confirmed by Sun's spokeperson.
(Also note that the national labs, who have been continuing ZFS on linux, are immune to a lot of these issues. Oracle literally cannot get an injunction against them on patent infringement issues, so they are guaranteed they can always work on it)