I think he was being sarcastic and trying to suggest that the original quote failed to take note that everyone thinks they are immune from those problems, including the person who decided the past was 'wrong' about them. I'm also pretty sure cousin_it is Russian, if that's relevant. The USA thing was just a tasteful addition, the way I see it. I laughed. (His use of an exclamation point and a look at the top contributors list on the right also indicate sarcasm.)
Edit: I agree with Nick below. It was just a joke. Which I enjoyed.
When I read the original quote, I noted the conspicuous absence of any kind of positive assertion that the speaker is immune from those problems, and I read it as cautioning us against thinking that we are not similarly wrong about some of those very problems and other important problems that we are blind to.
A monthly thread for posting rationality-related quotes you've seen recently (or had stored in your quotesfile for ages).