But mouser, they did try to get him involved. They've been trying for the whole two years that they worked on it. And he either (a) ignored them or (b) denigrated them on social media. Look at some of the links involved.
And truthfully, I think if they started out with the commonmark idea, they would have gotten the same reception from him, and others- that they stole it, etc. By starting out in the Standard Markdown space... they shed a lot of that... then moved to a better space where they could say that they tried to bend over backwards to make the spec part of markdown... but were put off at every turn.
When *finally* (and I use that word for a reason) he stopped being passive-aggressive, and said that he'd not approve any permutation of Markdown with their project, they moved. And the having to get a blessing from him? there are so many uses of markdown in a name that he had nothing to do with. I'm sorry... if you want control, don't make it open source, trademark your name, and protect your trademark.
He used a bastardization of an open source license... and no one is calling him on it is the other thing that's crazy.
But I think Jeff says it best in this particular response:
I do not want stewardship over Markdown. I want it to be a viable, community maintained open source project since millions of people rely on it. That is what open source is supposed to mean.