He made tons of mistakes but so does most mob bosses castellano more than most
Understand Castellano was hit NOT because of 'his mistakes' (Piccolo, white vs Blue collar, was Paul a business man or mobster, he wasnt 'from the streets' crap etc etc) but because Gotti was FORCED to.
Any justification beyond this is bullshit. Gotti hit Castellano because his hand was forced (ambition being an added bonus) NOT out of any retrospective pseudo-bullshit justification.