You are strictly correct. File system permissions are different from "allow" (permit) or "deny" (do not permit) htaccess permissions. Slip of the mind. So shoot me.
I wasn't trying to start some deep neurosurgery here. I merely wanted a question answered. Why you want to drive me off into the wilderness -- now you're on about choosing themes -- I don't know. Happy new year already.
You're telling me that the ajax is required, not optional, in the backend.
Fine. Thanks for the answer.