they are not saying that they are getting rid of all windows machines full stop, they are saying that none of their employers can use windows machines as their dev machine / work machines. They don't want to expose any private data to the windows machines. They certainly will keep around some windows boxen for testing purposes.
Big difference between "I'm gonna mess around on this windows box for an hour or two a day to see what it's like to use" and "this is my machine and it runs windows"
