And it makes rats like Tommy Ricciardi and Anthony Accetturo look better if they push the theory that Anthony Luongo was tapped to be boss first. Because that means Amuso and Casso infiltrated the boss position. And they were trying to take what wasn't theirs from the Jersey faction of the family. And it makes their (Jersey faction) position in the family look more untenable, and their decision to be rats more understandable.

Amuso and Casso may have been maniacs but a lot of the shit that's said about them seems a bit overblown, like D'Arco's account of the ambush at The Kimberly Hotel, and Casso crying to D'Arco and telling him he loves him when he was giving him the acting boss position, and Casso saying he wanted to kill a list of family members because they were "creeps", and Amuso not being able to look D'Arco in the eyes.

The reason for that is probably because D'Arco disgusted him.

D'Arco lays a lot of shit at the feet of other people, but he undeniably used the acting boss gig as an excuse to swindle money from the Family coffers. And he raised an unreliable junkie as a son, and brought him into the family fold.

Other people have said that D'Arco was a bully in prison and picked on weaker guys or guys that were lower on the totem pole than he was.