Appropriately for the thread, the WP scene had a choice: walk away. It kept telling Walker to walk away. The player could have shut the game off.

That's the pivot point: if you're just playing a game about Walker, then having a choice doesn't matter, you're just being told a story about a lunatic. But, if Walker is a stand-in for you, and you're playing the game "because you wanted to be something you're not - a hero", then not only is playing on a choice, choosing to play war porn in the first place is a choice.