All of that makes sense, but imagine you were hired away from a job at a great company within the last year. You probably can't go back, you haven't vested and you're essentially being pushed out after you were lured there with the promise of being able to work remotely. I understand that these people are free to quit, but that doesn't mean Yahoo! hasn't put them in a bad situation.
I agree it's worse when a company does it to an employee. Being forced into changing a job can have major negative effects on an individual's life, whereas Yahoo! will probably be just fine if any single person decides to quit.
It doesn't change the fact that it can happen, and this is a good reminder to the rest of us who have things promised verbally in an employment offer to have that stuff in writing. I am writing this as a warning to others and my future self.
