It's completely expected for a company to get rid of individuals on the payroll who are badmouthing the company they work for.
Why would anyone willfully employ people to work against the company's interest?
Thing is, part of Googles identity is "don't be evil". A vital part of this is stopping whenever you (unintentionally) do something evil. This should not be a problem for Google at all or reason to loose trust in an employee. Unless, of cause, the company has changed. And that's what those story's area about and why we need them: To make sure the public image of google actually reflects what the company now actually is.
Btw: To those saying "why don't you just quit as protest"? For one that makes it easy to be dismissed as disgruntled ex-employee. But more important is the same reason you don't just leave your country of family whenever you disagree or have a problem with those. Cutting ties is a last resort that shouldn't be necessary.
Publicly badmouthing the company you work for is indeed sabotage.