Kobayashi is a high schooler, and he is already decent behave compare to his peers. Yes, he can read people, but that doesn't mean he has experience dealing with people; those are not the same.
He is not a bad guy, just his mannerism not refined.
One theory of mine is that those cavemen are like Leafcutter ants. These famous ants carry a unique type of fungus that is said to be one of the oldest. The ants are the only one be able to nurture and care for the fungus, and the fungus feeds them food, a co-exist that collapses when one side...