The banners that purport to state the reasons for closing on this site are, more often than not, misleading. This is because (1) the banner displays only one 'reason' from a short menu or standard reasons, which is chosen by some algorithm out of the different reasons that different voters may have picked from the menu, and (2) people often vote on the basis of some gut feeling that the question ought to be closed, and then choose whichever reason on the menu seems close, even if it only very roughly reflects their gut feeling.
This is an unfortunate state of affairs because it is frustrating and alienating to new contributors, who often take the posted reasons at face value. Numerous meta-questions about the reasons for closing make it clear that this is a real problem, but it is unlikely to be remedied any time soon, because revising the menu of the standard reasons for closing is a daunting task.
I suspect that in this case the real reason why the question was closed is that the answer to it is far too obvious (the sense that the word has in everyday contexts is not the same as its techical sense in the law of contracts), but that's only a guess.