[SOLVED]
I figured out what the culprit is. This is an older system and the intent to purge was based on the assumption that some old config or other depricated element might be still hanging around. So doing this here:
apt purge x2goserver x2goserver-common x2goserver-dbgsym x2goserver-extensions x2goserver-fmbindings x2goserver-printing x2goserver-pyhoca x2goserver-x2goagent x2goserver-xsession libx2go-log-perl libx2go-server-db-perl libx2go-server-perl
Fixes it. It removes all traces of x2go from the server, only when you especially mention each and every one package and purge it does it work, for example the users are contained in the x2goserver-common package, if you just do a purge of x2goserver alone, that leaves most things still on the system. This gives you the possibility to wipe the slate clean and install it like it was a brand new linux install.
Oh, indeed, you should have purged both x2goserver and x2goserver-common... maybe also the old db packages.
It looks like in your original message, apt-get only tried to purge these packages:
The following packages will be REMOVED: x2goserver* x2goserver-extensions* x2goserver-fmbindings* x2goserver-printing* x2goserver-xsession*
So definitely not everything, for instance x2goserver-common is missing there.
Mihai