I think you are not taking into account that he's writing this for a, what i would call, moderately technical audience. In a sense it -is- a man in the middle attack as someone seems to have tried to put himself between the internet user and the requested service. To explain it as such at least makes it easier to understand for 'normal' people even if it's not 100% correct which in this case for this audience is just not that relevant.
A "man in the middle attack" is not about sniffing traffic going between two other people. It's about impersonating the two people to each other - telling Alice that you're Bob, and telling Bob that you're Alice.
