Because he would have been fully briefed on what he was policing that day , do you really think they just turn up and stand around , he told lies , expounded political views and was rude and aggressive , to say he wasnt is an insult to peoples intelligence.
He was clearly exposing the lies the bloke told , do you think the be videoing the conversation if the copper hadnt lied , and perhaps the copper should also be taken to task for espousing political views whilst in uniform.
Were.you there ? I was , there is a definite agenda for the police to be heavy handed and cause trouble , with routing antifa in the way of the march to just generally lashing out