[whpalmer4]

It also doesn't seem fussy to me, perhaps because OmniOutliner works in exactly the same fashion, so far as I can see.

It's logical, I think. When you are editing a row, if you paste something, you'll get the whole thing (in your case, several lines) pasted into that row, right where you pasted it. If you are outside a row, you get separate rows pasted in at that spot.