Ruining someone else’s contest just to make your point is what people would call a ‘douche move’.

Most forms of protest must by definition cause inconvenience in the short term to create the possibility of positive change in the long term.

Would it have been better if someone had earnestly submitted an AI “photo” and accepted the prize quietly instead?

Reducing this to just a “douche move” seems to miss the forest for the trees. The contest will cease to exist or at minimum cease to have any value/meaning if AI submissions become the norm. An alternate framing is that such a form of protest is a necessary inoculation to prevent infinite “douche moves” going forward.

It’s a douche move because it’s ruining something that is based on trust by betraying that trust. That’s not a challenge, it’s not helping anyone, it’s not high and mighty, it’s just that, a douche move.

Look at how much praise athletes got by proving they could win contests using doping. They got none because it’s a douche move, even if it’s technically not illegal it’s still cheating, even if they never pick up the prize it’s still ruining the contest. Everyone can imagine you can win a race on doping, nobody learned anything.