Certificate manager in an addon? What?!
And yes, they are so bad to the point they are harmful, but the only reason they are in there is because Firefox has it's own certificate store, more of a portability quirk than anything.
His point was, and I agree with it, that a mass browser does not need to expose cert management in a way that the 99.9% can access it because it's likely to cause more harm than good for anyone who is not capable of jumping through a few extra hoops to get to it.
Like removing the certificates manager. Or cache control. Or the ability to restrict cookies. Or JavaScript. Or the ability to turn off menubars, should you so desire to do so (kiosk mode). All of these things are used by people. Just because he doesn't like it, doesn't mean others don't want it.
Can you defend the SSL 3.0 and TLS 1.0 checkboxes?