The overriding principle is normally about driving to the conditions, not achieving a "target" speed.

This is one of the core problems of the car culture: ignoring the envelope except where mandated by law. A speed limit means, literally, "you are not allowed to go any faster than this" - but is interpreted as "you are supposed to go at this speed, or better 5 above". Nowhere else is this so prevalent: "there are 50 apples here, so you can't eat any more" is "you must eat all 50 of them" by the same logic.