I find the WP scene works better if you view it primarily as a criticism of the death from above section in modern shooters. The original plan to have the game diverge by allowing you to not do it would have undermined the point it ended up making about how these segments in the shooters of the time were railroading you into committing atrocities and then patting you on the back for it.
Its also the first major point where Walker diverges from just being the self insert and becomes the deconstructed military shooter protagonist with some aspects of the kind of person that plays military shooters left in which is why you see the "its guilting me for something the game made me do", it only attacks Walker the character for doing it, the guilt trip loading screen messages are aimed at the player for picking up a game where you shoot foreigners for entertainment in the first place.
The best part of the scene in my mind is the immediately after where he's attacking the un-mortared command centre of the gate and desperately hoping for some secret revelation because in a regular game of the type they would stick some meaning to justify what just happened instead it was for nought.
I do find it interesting how hyperfocused people become on that scene, its far from the only atrocity you commit in the game (I think the aquatic Colosseum is far better executed too) but I suppose most people just block out the fact that they gunned down refugees or slaughtered masses of deserter soldiers so they can make more refugees die of thirst because theres no burned baby at the end.
>Apocalypse Now is still the best piece of fiction dealing with that subject matter
I agree there, it really captures the spirit of the book which the game pretty much doesn't beyond the descent into madness and critique of something that was popular in society at the time.