It's have friends in the party or just roll over and do as we say. The "letter" does not matter. Remember the letter literally says there's freedom of speech there. And why did Google leave? Haha.
This works for Chinese businesses pretty well.
The problem for Western businesses is that "Creating domestic competition to any Western business with a comparative advantage which becomes too important to China" is always, on some level, a national priority.
My favorite Party explainer - https://chovanec.wordpress.com/2011/05/08/primer-on-chinas-l...
The incoherent views of the hn user: "We need to do something about the corporations" but also "China is evil for doing something about the corporations"
They can and will change it later.