I'm not sure I buy this type of attack. How is this different from calculating yield of a bomb as Fermi did? It's back-of-envelope calculation that physicists do all the time. Ping Pong in a Boeing is merely a setup with the least context. This is like criticizing a math teacher for asking elementary students to calculate how long it takes to fill a swimming pool when water is flowing in and out of the pool at the same time. Yeah, the setup sounds ridiculous, but you know what, that's the setup that a student understands, and we see similar scenarios in real world: a company earns and spends at the same time, a queuing system has incoming traffic and completed tasks, a factory has incoming jobs and outgoing completed products... So, what's wrong with the question again?
Frankly, the fictional Feynman in the article sounds confrontational and arrogant. Take the manhole question for an example, all the counter questions are either nit picking, or rejecting the value of industrial design. Of course there is a reason for choosing a round shape for manhole cover. Of course there is a trade-off among different shapes.
Please note, I'm not saying the manhole question is good for interview, but it does not mean that we need to be mean and resort to cheap attacks to make a point.