But one would assume you would mention the failure of the organisation to address your previously raised concerns in your resignation-and-criticise blog post?

Indeed. I feel for this guy. I volunteered with Mozilla for a long time and I have a lot of love for the org, but there are cultural/institutional problems it inherited from Netscape that are still there today. I think people of good conscience can't help but state why they're quitting in situations like this. We still want the problem fixed even if we can't fix it.