[ghostbrainalpha]

You are right that letting the acquired company "do whatever they want" wouldn't be Amazon's jam.

But the Zappos case was different. They didn't NEED to sell, so they put in the selling agreement that they get to keep a bunch of autonomy.

Basically Zappos loves being a part of Amazon for shipping and logistics benefits.

But Zappos core strategy/identity is based on being an uncommonly fun place to work and being great to its employees. They wanted to make sure when they sold that the never had to deal with employees "the Amazon" way.