The SDK is not closed source, you can find the source here: https://github.com/bitwarden/sdk
It might not be GPL open-source, but it is not closed either.
Sure. To me "source available" is still closed-source, since looking into it might give companies an attack surface for you to have violated their copyright in the future. Happened with IBM in the past: https://books.google.de/books?id=gy4EAAAAMBAJ&lpg=PA15&pg=PA15&redir_esc=y#v=onepage&q&f=false
Let’s wait and see before we get out the pitchforks.
Sure. Bitwarden doesn't owe us anything, but it is still sad to see this decision and better clarification and explanation could have alleviated the breaking of the trust here.