He's a Chinese player so probably doesn't speak English and was confused at what to do in the battle, I doubt he was trying to intentionally grief.Giving it up to confusion loses its luster when he's specifically breaking our own constructions/shields and throwing 1 material at multiple construction sites throughout the duration of the battle.
Would be nice if leaders of a battle could kick people from their roster during the battle incase they hire someone who does especially bad/griefs or whatever, would be alot simpler for everyone imo.