If somebody smashed an object over my head unexpectedly I might also instinctively lash out and strike them. If I had five or ten seconds to think about, it I wouldn't.
On the other hand...
a) I'm not a racist Australian politician
b) However I almost received as many votes as he did
He's not defending the politician he's pointing out a simple fact that people when surprised with sudden "violence" can and do lash out.
Nah, fuck that. He turned around, registered it was a kid and hit him anyways, then he hit him again, then his goons choked him out, fuck that dude and his goons.