It’s because the content was likely preprocessed for broadcast news. Which means normal 16:9 landscape format.
Vertical video has done nothing but introduce constant issues. I used to be a guide for Jeep runs, and I was also the video editor for the run videos (just clips from the run with music). And naturally you can’t be everywhere, so 95% of the clips have to be recorded by everyone else. Even though they were told “don’t record vertical video because we can’t use it” they did so anyways, and were upset when we couldn’t use their videos.
And to be clear, this isn’t just a random video. We’re talking about a large organized and legally registered club, so we kept everything to a certain standard of quality. Vertical videos are not suitable for anything except a phone.