I’d guess some of those are the stupid “idiot boyfriend films unknowing girlfriend” type cruel and tragic shenanigans, but it still does illustrate a point. Shotguns are rough to shoot compared to ARs, especially for people who are smaller and unfamiliar with them. No one who is handed an AR has any problems with them, even if unfamiliar and using a terrible stance. They’re especially easy to use compared to shotguns, which with defensive loads are often rather punishing to shoot.
The girl at the end of the video is using a weak stance that’s just as bad as any of the shotgun girls, but has no problems firing the AR, she isn’t knocked on her butt, and she turns to the camera not with an “ow!” or “oh crap!”, but a “hey, this is fun!” look.