I think it's because, in real life, you can tell who's looking at you and when. There's key components of body language that are based in who is paying attention to who. In a videoconference, this is all missing. You can't tell who's looking at you or not, so that mean anyone could be looking at you, so you act like everyone is looking at you all the time, you feel the need to control your presentation more, that cau…
I don't do video calls, but my partner does them often for work. The other day she mentioned that you're able to see who is looking at your video feed because their eyes looks directly at you (akin to them looking into the webcam). I'm not sure if she was mistaken, or if there's some kind of eye tracking/image processing stuff going on to do this. FYI it was Microsoft Teams.
And poor her - big Teams meeting are actually awful and large meeting with it are not good.
A lot of my team members were in Australia which appears to have dismal internet, a terrible connection to New Zealand, or both.