Eh, unreasonable hate towards someone simply because they "stole" the spotlight, and it was once, I think it would make more sense if he was trashtalked after saying the classmates should stop the search, and about that...where the fuck where the adults?
The guy idiocy is too forced, the attacks were already nullified by the slime, no one with a working brain would go with the same attack on a powered up version, and after being told why the attacks don't work? I know pride can blind people but he literally already knew his attacks were useless, to continue out of hate for the person giving the advice...bad writing.
And then he changes his years long target of hate from the girl to MC and screams his whole name, when MC literally did nothing to him and in that meeting stood back, all so that rich girl hears it.
Think about it, MC acts towards this asshole were literally ignoring his though talk and saying how they could win, he never declared hostility or insulted or obstructed the prick.