Because: Video Rotator is the GOTD
A couple of quick notes on rotated or rotating video...
A video file may have flags set saying in effect which way is up, but it's up to the player to decide whether to look for &/or obey those flags. Many do neither. [You run into the same thing with DVD video, where players may not honor flags to expand the video, or may expand all video in anything close to DVD frame size regardless.] You can (re)set those flags using ffmpeg without re-encoding -- Google for directions.
Re-encoding video unavoidably loses quality -- you cannot rotate video without re-encoding. If the orientation is a problem, use player controls to rotate the video on playback.
Tall cell phone video Is A Thing. That doesn't mean video shot on a cell phone in landscape [wide] orientation is a bad thing. Nor is video shot in portrait [tall] orientation bad -- it's the default online. Saying someone screwed up because they used one or the other is bad, unless you're talking about how it fits templates for whatever sites, e.g. Facebook.
A video frame is like a still picture or image -- you can crop it all you want, but you cannot change its aspect ratio without distortion. Changing the height or width only works well when you change both height & width proportionately. It's common to pad the sides or top & bottom with solid black to make the video frame fit some size requirement [letterboxing]. That usually adds to the video file size, plus requires re-encoding. Often players have settings where they will add any needed letterboxing themselves -- a much better solution.