@thrrgilag Remember that sharing the code under an open source license doesn't mean someone doesn't own the code and can't make decisions about what gets committed to the official code branch.
The real issue (as I see it) has nothing to do with Open Source, but rather allowing those who use forks of the official Signal clients to connect to Signal-maintained servers. As that's a service Open Whisper Systems maintains irrespective of the code that runs it, they are well within their rights to restrict who can connect to it with what clients.
// @matigo