Feels like the crow girl is salty that he just accidentally turned this revenge tragedy that she was relishing into an incest love comedy (?).
Also I'm now lol'ing at the title, "BAD MOVE".
(In all seriousness though, I suspect that it's called a "bad move" because Aqua won't be able to throw his life away so easily when he knows how important he is to Ruby. After all, while it's true her star is invigorated out of love, she's still fragile; I still wonder how she'll react when she finds out about her mother, and how that will play into her character development now that she's straight on in love with Aqua.)