In context: Dijkstra noted that IT discipline had strong regional tints, enabled by some "«malleability»" (over which the particularizing forces are applied). This "malleability" follows very fuzzy definitions of purpose, which he exemplified through a von Neumann that resembled medieval scholastic philosophers and an Alan Turing that proposed (to the judgement of Dijkstra) "irrelevant" perspectives in the same direction, such as "whether submarines swim" (for "whether computers think").
Now: the context instead of this branch of discussion is about those "signs" noted by OP, which I note are overwhelmed by evidence that those signs are doubtful. The point is not in the vague metaphors that Dijkstra found confusing, but in the opposite flat matter that "whether it swims or it "submarines" [as a verb], it has to do it properly". Which is not in Dijkstra, because he was speaking of something else.
It doesn't matter if the thing a submarine does is "swimming", after all.