Of course Linux can do this. I'm writing this very reply on a Linux system booted directly off a ZFS dataset.

    % zfs list rpool/ROOT/default 
    NAME                 USED  AVAIL  REFER  MOUNTPOINT
    rpool/ROOT/default  14.8G  60.1G  11.9G  /

Support for this exists in GRUB and initramfs-tools, and it works perfectly.

The GPL is not an EULA. It's a distribution licence. There is absolutely no problem in using ZFS on your system, and there's no legal restriction on what an installer may or may not do.