I have no doubt at all that if NSA knew about this bug, they were exploiting it. That's what they do. It is not my argument that this bug is irrelevant to NSA.
It's unlikely that Apple would agree to sabotage their own products in a way that will eventually be detected and affect their own credibility. That's restricting the argument that people are making to a straw man, though. Have spies ever worked that way? What people are mostly speculating about is whether this was an intentionally introduced vulnerability, not the mechanism by which that would come about.
Let me give you the perspective of someone who is outside the security business but knows a good deal about PR and the media and how it operates. And selling books (one that I was doing was mentioned on the front page of the WSJ - all from PR that I organized on my own).
Schneier has certainly transformed himself and it's all about his image and selling books with his new found fame. I know it when I see it. Because as he just said in a way "it's what I would do if I wanted to..."
So in other words he has an axe to grind in getting mentioned in the media. Period. That doesn't mean what he is saying isn't correct in some fashion of course. But it does give credence to the statement "Another sad indicator of the level Schneier is playing at today". That level is publicity for Schneier. So to repeat myself, exactly what I'd be doing if I was him.
In other words, you're not being objective. You already attribute good character to the people you know at Apple, and are therefore are looking for ways to defend them against an accusation that hasn't even been made. The fact that you unnecessarily called Schneiers current occupation as 'sad', imo, tends to support this rationalisation.
None of the issues with Flash or certificate verification bugs you bring up are relevant to the discussion Schneier is having about this being the perfect kind of backdoor, and that, if it were a backdoor, it would have been hugely successful over the last year or more.