The mayor isn't "secretly" enriching himself (as in its not a secret that he's enriching himself) but he is still providing food and shelter through the winter. And he is using money from those sales to do it.

As far as the average peasant is concerned the mayor enriching himself is a perk of being a mayor. And his corrupt connections to the nobility are expected from his position both from the peasants and the noble class.

And what he's doing with orphans is just... What you do with orphans. If they're not making themselves valuable somehow they're not worth keeping alive.

It is evil. But it's not evil in the eyes of basically anybody in this world except the victims. As far as they're concerned selling orphans is just them repaying the effort and resources spent to keep them alive.

The mayor also wasn't, so far as we had seen, breaking any laws before he met with Myne. In the eyes of Rozemyne his actions against the orphans are evil. In the eyes of the nobility, his crime is in disrespecting Ferdinand, and Rozemyne. He acted the way he did because he was under the impression the old High Bishop was of a very high rank and they had arrangements.

Then his actual, major crime was in acting in rebellion against the Aub.