Quite honestly, I don't know why we shit on ACs just for being ACs. It's the same thing as an ad hominem attack, which we regularly condemn here.
In reality the AC is correct and the grandparent is incorrect in his assertion that, "There didn't appear to be any motive for the assault other than a fear of his prothetics." Grandparent is apparently unaware that essentially all information regarding Mann's incident comes from his blog. There was thorough discussion on Slashdot about possible motives and I think it was generally agreed upon that the reason for the attack was a perfect storm of a) language barrier b) Mann's disregard for the rules of McDonalds, and from what I gather, unwillingness to leave (no filming or pictures) and c) McDonald's employees who are currently trying to keep their restaurant, which is currently under protest, from going under.
All this being said, AC's comment, though correct, was inflammatory with the "state facts or STFU" spiel at the end. It looks like there are only losers here.