They were contractors. Google isn't their employer and can't sack them. All they can do is ensure that they no longer work on Google projects.
And the term "sacked" can certainly be used to apply to service providers / contractors:
http://www.governoruduaghan.org/infocus_listing.php?head=3... http://articles.timesofindia.indiatimes.com/2009-11-18/delhi... http://www.telegraph.co.uk/culture/tvandradio/3741846/BBC-sa...
I'm saying the writer at Verge should not have used the word "sacked" because it does not accurately describe the situation.