From Bing:
met·a·phor
NOUN a figure of speech in which a word or phrase is applied to an object or action to which it is not literally applicable:
"“I had fallen through a trapdoor of depression,” said Mark, who was fond of theatrical metaphors"
Not seeing it. It looks to be a more literal than metaphorical usage.
That is your opinion. The rest of us do not take it literally.
Evidently metaphor is also in the eye of the beholder.