So, the proper, open-source-if-a-bit-dickish way to go about this would have been...
1) Microsoft forks the primary git repository and declares theirs to be "Microsoft-blessed".
2) Microsoft puts a skeleton team in charge of maintaining the Microsoft-blessed version, but mostly they just pull the original maintainer's patches.
3) People slowly migrate to the Microsoft blessed version.
NOT: We flipped this hidden switch under the table and now your repository in GitHub is controlled by us.