Among other things, the Mossynoeci wanted to have sex in public with the courtesans accompanying the Greek army.
That must have seemed weird to any pederasts who were in his army.
Even Greek men who had a positive attitude towards pederasty (Xenophon seems to have been one of them) generally married a wife in order to have sons to carry on the family. The behavior which appalled the Greeks was having sex in full view of everyone.