>>55183550He's massively insecure for one. He feels slighted that Orgepon, a living creature with free will chooses the Player, simply because "I liked the Pokemon first!". This means he didn't give a shit about the Pokemon's feelings, just that he wanted to be acknowledged by it. He's also mad that his sister gives him no respect even though he constantly fucking rolls over and takes it. You, the Player, don't and beat Carmine's ass over and over in a battle to shut her the fuck up.
He's just a jealous little bitch, plain and simple.