It was true that you had kidnapped this child, changing his name 'Mexico' and naming it New Spain.  You passed him off as your son and, really, 'New Spain' didn't put up much resistance, except for the first few days.  You started giving him punishments, that's why he no longer struggles with you.

No one knew that you had murdered his real parents and kidnapped him.  And they really didn't need to know, why know the truth when you can just live in a fantasy world?

'New Spain' was curled up in the corner of the room sobbing.  He had received a punishment from you, a punishment more painful than the previous ones, since apparently he has the strength left to be a rebellious brat.