Although not my fight... and I am not one to get between a hunter and his prey. However surely your 2 questions to our fellow poster amount to the same thing?
Or "are you just ignorant"?
Asking "Do you really not understand this or are you just that ignorant?" can indeed mean two different things. First case: Somebody is intellectually not able to get something, but as this limitation isn't his fault, you can't blame him for this. Second case: Somebody simply is ignorant enough that he easily could and should get it, but consciously fades out the facts to not have to admit that he was wrong.
I admit, I didn't meant it that way, as the first part is quite mean, but as you've asked for it ... Challenge accepted. (and in advance: Please don't jump on my English if I used a wrong word in the explanation - not a native speaker ...)