As Biden gets into his speech, and for about 98% of the video - the framing is exactly as Snowden presented. Given politicians are the sort of people that obsess over the implications of the color of a tie, this visual was chosen absolutely intentionally: a flag hung vertically, blood red imposed on a dark scene, and two shadowy marines in the rear. I have no idea
why they went for this visual, but it's difficult to attribute it to any motivation that is at all desirable.
Incidentally, if you originally watched the video on CNN, I'd encourage you to check out your own link, past the 40 second mark! Because that leads to a much more light hearted (though not really, if you really think about the implications of this) issue. As this video was streamed CNN distorted the colors, in real time, to try to increase the apparent lighting while also turning the crimson red into something like a fuchsia pink. [1] If you think that link might itself be fake, feel free to just look at any of CNN's coverage [2] and compare it against the source videos.
Everybody understood exactly the sort of imagery Biden's writers were looking to evoke. The only question that remains to be answered is why.
[1] - https://twitter.com/burackbobby_/status/1565543514137677824
[2] - https://edition.cnn.com/videos/politics/2022/09/02/veteran-r...