Why Hemp Oil?

Why is Hemp oil considered healthy if it has way more poly fat than mono?
I thought that having too much poly fat over mono was a serious problem in the Standard American Diet, and that it is one of the reasons why nuts like peanuts are not recommended as opposed to other nuts who have a better fat ratio.. It would seem like adding Hemp oil would break that balance with it's relatively huge amount of poly fat over mono fat.
Am I missing something here?