He kept his rank and command, didn't he?That we know of
So, again, like Vulcans stripped of their ability to repress emotions turning evil, which can be interpreted as their "true self." They always return to duty afterwards, normal fare.Gary, on the other hand, arguably acted with his own free will the whole time. There's much less evidence (if there was any at all) that whatever that was in the galactic barrier, "possessed" Gary (in the same way the Borg do), or if it simply amplified what was already there.