Right is right. I've sold and/or loaned reels to anglers who are left hand retrieve. I ususally do them the courtesy of unspooling, reversing bearing directions and respooling. Sometimes putting on a lot of backing and a line with left handed winding is a long chore. In some of those instances left winding was so painful I had to take a beer break.
To change direction, flip over the gear, re-install the gear (super simple), flip over the cassette, and done. Don't have to mess with the line or the backing. The STH cassette reels are awesome loaner reel . . .