Did you see the scare quotes around 'wall'?
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Scare quotes are a particular use of
quotation marks. They are placed around a word or phrase to indicate that it is not used in the fashion that the writer would personally use it. In contrast to the nominal typographic purpose of quotation marks, the enclosed words are not necessarily quoted from another source. When read aloud, various techniques are used to convey the sense, such as prepending the addition of "so-called" or a similar word or phrase of disdain, using a sarcastic or mocking tone, or using
air quotes, or any combination of the above." -from Wikepedia