yeah... um. Why would Signal (OpenWhisper) sully their name by coordinating efforts with MS? MS doesn't have a great track record at being an advocate for privacy or user security...
The mission of OpenWhisper is to bring e2e encryption to the masses, not to make Signal the messenger the dominant IM tool. They succeed spectacularly by making the popular IMs adopt Signal the protocol.
Considering they partnered with facebook, they don't quite see it that way, instead looking at it as a way to bring good e2e crypto to millions of people.