You are wrong. He is what we call here an "αντι-εξουσιαστής", which roughly translates to "anti-authoritarian", but it's not that simple. Basically, they are a form of anarchists who believe that man should hold no power over another man. They are extremely chaotic and always try to cause riots.
This photo was taken during the riots of December 2008 in Athens, after a cop accidentally shot a 15 year old boy during a verbal confrontation.
As a side note, I see no defiance or bravery in this photo. During such events, the Greek police is usually ordered to stand down and not engage with the rioters. When attacked, they retreat. Therefore, the guy is throwing a molotov cocktail on people who literally can't harm him. Nothing happened to the guy.