Just because he made some massively incorrect assertions while at Google does not mean he is not worth listening to. Everyone says incorrect things sometimes. I mean, can you claim that you are right all the time? Probably not.
I don't know him personally but I read the stuff he writes, and while his character can be a bit abrasive he's an extremely intelligent dude who can make astute observations and connections that other people miss. I think you're doing him a lot of disservice by dismissing him the way you did.
Not reflecting on this case specifically, but if six months isn't long enough for a new employee to generally understand how a company works, it would seem to suggest something's wrong with the company's culture, or at least with how people are brought on board. Six months is a long time in an industry where people change jobs every two years.
Part of the problem with mchurch was willful ignorance. A few colleagues, including some fairly senior people, reached out to him and volunteered to try and help him resolve his concerns. To my knowledge he never took them up on it.
I consider myself to be consciously observant of organizational issues. I would say it took me about 4 years to develop a reasonably rounded picture of "how things work" at Microsoft, and then only from the point of view of a low-ranking employee. Big companies are vast, layered, intensely game-oriented social universes.