You seem to allude to the fact that it really isn't that easy. In fact, if it is truly an AGI then by definition we can't just box in its values in that way/make one arbitrary change to its values.

Instead, I would say if you don't want an AI to treat us like we treat cows, then just stop eating cow flesh/bodily fluids. This seems a more robust strategy to shape the values of an AI we create, and furthermore it prevents an enormous amount of suffering and improves our own health.