i am not sure if i am missing anything, however the footage shows the man was among a group of people trying to pull a statue down, the first scene in which he appears clearly shows he was struck with a skating board by the crowd. probably he didn't want the statue pulled down, and he was beaten because of that.
the man then walked away, he tried to signal to the people beating him to stay away, they didn't, they followed him, and assaulted him, threw him on the ground and were again beating him with the skating board.
only after he was still being assaulted on the ground did he resort to using his hand gun, so from his perspective, he can rationalize acting in self defense.
now as far as pulling these statues down, it is not for the mob to decide what statues to pull down. not much different from the thugs we have seen on our own roads in Lebanon lately.