Big penis humiliation is not possible. Nothing anybody can say can humiliate or embarrass someone with a big dick as, in order to humiliate someone, there needs to be a negative/undesirable aspect trait or characteristic, as none of that exists in a large penis, nothing.
As far as the classical art argument, small penises were not necessarily perceived as desirable in a purely sexual aspect. It was what it represented (reason, judgment, self-control, etc) unlike the large one representing lust, abandon, etc) in essence the large one was physically sexually desirable.