It could also be both. I have found that we sometimes have conflict over things only because we don't understand the bridge between them. Same as the conflict over whether Christ rose with a physical body or a spiritual body; when really it is both. He rose in a physical body (hence the details about him eating, and his wounds), but He 'shed the flesh' to enter the spiritual realm. That really does take care of that conflict.
It could be the same in this scenario. But in either case... as a result of that union between the sons of god and the daughters of men (spiritual or physical or both), the world became corrupt and the source/result of that union was 'washed away'.
Peace,
tammy