It is sane and factually correct.
> Plenty of open source projects consider themselves a community which welcome newcomers, take governance seriously
Rich is taking governance very seriously. Others aren't and give nobodies the right to vote. In any case, he's factually correct. Nothing in open source implies anything about any type of governance, as "Open source is a licensing and delivery mechanism, period".
> Acting like a jerk
Pot, meet kettle.
Everybody is entitled to say (but not dictate) how something should work. Holding and expressing opinions is an innate human right, and the developed world only takes it away in extreme circumstances. Talking about open source governance is not an extreme circumstance.
We are not legally entitled to basic politeness, but politeness is enforced socially rather than morally, and failing to be polite means risking social consequences. If I used Clojure and I read the linked article, I would avoid hiring Cognitech, which is the exact problem Rich mentions.
Calling this offensive and inflammatory can only come from someone who is extremely conflict-avoidant. For my Italian sensibilities, it's quite milquetoast.
Your counter argument to this is to just be contrarian and imply they are a jerk... because, well, you don't agree with them. You didn't add substance to the discussion (facts, evidence, argument seeking middle ground), you just sought to set fire to someone because you were uncomfortable with the dim prospect you might be wrong/guilty of acting like this/be the subject of the criticism.
Do you see how this undermines your point of view/actually re-enforces the validity of the criticism?