There’s a multitude of things the PC western world needs to fear more than guns in the hands of peaceful law-abiding citizens. The collective lack of a spine for one.
The people who push this are statists, who believe that only the state should be able to use force. They like the idea of the state as an all powerful entity without limit.
The State is their god.
The thing is Nick D'Arcy is not a peaceful law-abiding citizen. He's a violent thug with a criminal conviction for assault occasional grievous bodily harm - in US terms, a felony. He was lucky to escape with a suspended prison term.
His crimes - committed against a fellow athlete - lead to him being dropped from Australia's Olympic team prior to Athens, and from being allowed to participate in the World Championship. He has been very lucky to be allowed a second chance and for this reason, he is expected to be exceptionally careful with the way he behaves. There probably would have been some backlash anyway over these photos whoever was in them, but the fact that it is him makes it far more controversial.