I don't understand, will they be invulnerable to Chinese hackers after removing the Chinese version of Google?
My guess is there's a lot more to this story Google's not willing to put in an official statement.
The current events are troubling, but I imagine the decision makers at Google are also looking at the long term implications to their business.
That is to say, even without the current crisis, China as currently governed and managed may be a poor long-term bet for Google. Both in isolation and as part of a world economy still in the process of being defined and subject to influence by decisions such as this.