I'm not a lawyer. I don't k is what Oracle's lawyers can and can't do. Even if I'm legally in the right, Oracle's lawyers could break me if they wanted. I can't know if there is a ZFS grenade, and neither can you. But we can choose to not deal with Oracle.
At that point, if they wanted to, they could sue mort96 for saying something bad about Oracle. It's unlikely they'll do that and perhaps a bit less unlikely they'll sue over ZFS.
Most of their legal shenanigans appear to be restricted to companies that already license some software from them.