If Gruber says no, then who else besides him is to blame for needlessly attempting to block Markdown's forward progress, especially when it is seriously in need of attention, and when he has not put in any effort to give it some?
The person at fault would look like Gruber because the person at fault would be Gruber.
I sympathize with Gruber's apparent position, which I would summarize thusly: "Markdown is /this/, which I released; it is good enough for me; if it's good enough for you as well, use it; if not, feel free to make something for yourself instead".
I don't think he is saying that. Jeff Attwood is (I think) asking him to say "I approve, this is going to be a Markdown Spec" or "I disapprove" - in which case it will be a Rockdown Spec.
It seems to me that Gruber is adopting a 'Trotsky at Brest-Litovsk' position - "no war, no peace".
The person at fault would look like Gruber because the person at fault would be Gruber.