We are a fully clean install. Meaning no packages except git are installed. No Apache, php, or MySQL. Why should the installer ask for root password here? It has never been setup before this point. There would be no password. FOG, in my opinion, should not be defining the root user password here either.
I think it should force the user to have a DB root password unless it’s a setup with local socket access as described below. That was one of the major points of re-writing that part of the installer. I tested a lot and would hope that the installer does what I say on all officially supported systems.