Yusaku experienced a lot of negative reinforcement in the Lost Incident: if he lost a duel, he was shocked and under-fed. I don’t think he’s consciously aware of it, but his experience has made him think that the threat of punishment is what makes you grow.
So instead of helping Go by giving a pep talk, he used
negative reinforcement.
(And then he gives
a “people don’t have limits”
pep talk anyway, but aims it at Dr Genome. Even though he’s just implied Dr Genome is about to win.)