Kokichi was a reclusive and reserved individual who resented being born without a future outside of the jujutsu world. He proudly admitted he'd give back every ounce of cursed energy to gain a normal body
Kokichi's resentment lead to him projecting on those undeserving. During the Goodwill Event, Panda suggested he and Mechamaru should get along since they're both cursed corpses. Kokichi took exception to this and thought of Panda as nothing more than just a doll.