So... they fired him for doing a 20% time project? I'm glad I don't have any of their stock to sell, what terrible management.
20% time project != able to just launch it YOLO style
I suspect the core issue here is that he launched it with Google logos without following any sort of process
Not for doing it, for releasing it publicly, presumably without permission. (If he did have permission, he probably has a pretty good case to bring.)