There's an explicit company policy about game development that is separate from their open source policy. It, among other things, prevents you from working on a game project with anyone else.
Games development are limitless in scope and technical complexity and very passion driven. So, a developer could spend countless hours each night improving his game.
Next day, all the team has is a tired developer, drinking coffee and unable to code straight or analyse issues without missing subtleties.
Opening a wordpress for your mom and her gardening hobby is a significantly less time consuming task.