I don't blame them for not knowing about things.
But I can blame them for complaining about it without checking, and thus making a fool of themself.
I argue that given the circumstances he would have been foolish to check something that looks like an obvious typo. Who checks on something obvious that they're certain about? His assumptions were logical given that he did not know that something called "Ancien Regime" existed. I do agree that in a vacuum complaining about a typo is silly, but given the state that the entire manual is in...
@Surgeon: I was posting in defense of someone else. Kind of ironic that you didn't check that when you're trying to give someone flak for not checking something.