I know what a hookah is, but only because I eat middle eastern food. I also know what a bong is, and that it is not the same thing as a hookah.
But I wouldn't assume someone is completely ignorant just because they don't know what a hookah is.
The kind of ignorance that really bothers me, is the kind like I mentioned previously, the guy who thinks people in Moscow, Russia are STILL standing in line to buy bread. That is a clear sign of someone who has been propagandized their entire life, and not only doesn't QUESTION the propaganda, but insists even when confronted with REALITY, that the propaganda is STILL TRUE.