I think you are moving
too fast here. I don't know that you have much of
an argument.
I listened to a radio program one time about some women from Puerto Rico.
They were living in New York, but they did not agree with the child
rearing practices that were becoming dominant in New York. They
believed in corporal punishment for children and the 'official' view
in New York was moving away from it.
Now these women were very critical of our child rearing practices.
Let's grant that their views were just as true for them as our views
are for us. How does that imply that they could not criticize our
practices?