He probably feared the real physical power of the blue collar faction, just the way Gotti supposedly feared the psychotic faction(Demeo crew)........Even though Paul took over the boss of bosses title from Carlo, when all hell breaks lose and wars are about to happen, I would want to side with the guys who reside in the trenches and know how to get their hands dirty.

In a war, rules are not followed and the normal order has broken down. Big Paul even said to his maid that the reason he was sad is because, all he has is money and, people like him die in the street! paul castellano just didn't get it.he should of been more aware of his street crews thinking,he was just so prosperous he was just out of touch. he would have survived if he had hit first,he should have made it clear to dellacroce that he didn't want herion dealing going on, and had neil put a stop to it, that's why gotti hit him. because paul knew about the drug dealing,gotti beat him to the punch.