Not the way I read it. The previous post seems to be suggesting the NSA doesn't have some backdoor into Windows that Microsoft put there for them explicitly, w

Not the way I read it. The previous post seems to be suggesting the NSA doesn't have some backdoor into Windows that Microsoft put there for them explicitly, while the followup suggests that even without such an explicit backdoor, one should assume the NSA can take control of just about any system with a network connection (which is probably not explicitly true, but is true enough that you should just assume it). The second suggestion being they (the NSA) have a (likely lengthy) list of exploits found in common OSes (and/or firmware or CPU microcode) that they have never divulged and that they have discovered like any external security research would have (albeit one with a very large budget and a very strong incentive to find such control vectors).