From my previous post: But GCM still requires a Google account. This is not just a problem for people who reject the Botnet, but also for others who have Google blocked in their country, e.g. China. (a big potential userbase who are in need of secure communication)
Well it should be possible to add an option in the app to choose between GCM and Websockets. But there aren't any signs of him doing that.
Yeah, he can write whatever he wants, but without being able to distribute it on a major platform like F-Droid, it's pretty much pointless.