Marisa types have been shown to be smart enough to use sticks for tools. They are also smart enough to leave a situation should they find it not easy anymore. While this leaves them to look like assholes, it is a sign they arn't stupid enough to sit there and take it.
Even if Youmu types are confined to saying nothing but "DICK!", The ability to use a sword of all things has to show it has some kind of higher brain function from the rest.
I don't know, I think they both turn and slaughter the ones in the back. Youmu and Akyu types are pretty smart, they must know when they are being used.