I'm sure they have people that actually legitimately give the wrong answers, but even in that meme you can see plenty of cuts between questions and answers given by people, For Example:
The first woman that was asked when the US was founded, the cut was obviously hidden behind the MS Paint session, then it comes back and she says 1995
After that woman he asks someone else, "Who did we gain our independence from", Footage Splices/Cuts as you can tell from the footage jumping, Guy Replies Korea, this is obviously Altered and they either didn't even try to hide it or they did a horrendous job at doing so
After that guy he asks the first woman who fought in the civil war, then the footage cuts again and she says Nazi's vs Germany, which whatever the hell she was asked she would have been wrong anyways so why make this pointless cut?
the Woman at roughly 1:04 mark, The Guy asks Who fought in WWI, You can see the video cut/splice, The woman says England, the footage splices again, he asks against, the footage splices a 4th time, she says the united states
Same woman later, "Did Germany Have any allies?", Very Obvious Video Splice, she replies "Poland?"
The guy that was asked about about Who fought in WWII and said Vietnam, that appears to be real as you don't see any obvious splices and the people in the background are consistent through out that question, so while they could have done a lot of video trickery to splice the left side of the video in to keep the background consistent, due to the abysmal lack of trying to hide the other cuts I doubt this one was faked unless the Source Clip was faked
The Pearl Harbor question it's hard to know one way or the other if that one was spliced since the question was a tight shot on the interviewer, then it went to a wide shot of the woman answering, the obvious splice section would have been the camera angle change but no way to prove it either way