In your original post you said, "They weren't all the scumbags the books make them out to be." Who were you referring to? Just DiNome? Or Testa and Senter as well? Because you mentioned the latter two in the same post and there's no way you could apply what you said to those two.
I'm with Ivy here, there is no honest justification for a bunch of amoral thugs, which essentially, is the primary definition for the DeMeo crew.
These guys were cold-blooded killers. According to informant testimonies the crew, headed by Roy, would follow a sadistic cycle upon murdering their victims. The crew would first lure their victims to an apartment directly behind the Gemini Lounge where they were shot in the back of the head by Roy DeMeo and the head would be swiftly wrapped in a towel. Harvey "Chris" Rosenberg would then stab the victim in the heart to stop the bleeding. Then the body would be left to drain in a bathtub for 45 minutes. After the body was drained and chopped up it would be left in a garbage bags while Roy DeMeo and the crew would order a pizza and eat it with their unwashed bloody hands.
Ultimately Roy DeMeo died the way he lived, as a street rat, in fetal position, in the trunk of his car. There is no sympathy or empathy from anyone including the Gambinos who he made so much money for over the years.
