I would say it depends on how the video is intended to be viewed. If the video is going to be consumed on a phone for example, vertical is no big deal and might even be a really good option. Just pick vertical/horizontal to suit whatever you’re recording and the story you want to tell. Neither horizontal nor vertical is inherently good or bad, the full picture must be considered. That’s my hill to die on.
Vertical video can also be excusable when the options are to either capture everything on vertical video or miss over half of the things happening that you want to record. Like when I visited a robotic lab and due to physical constrains could document a humanoid robot doing impressive stuff either fully (portrait) or partially (landscape). A bit annoying to display the vertical video on a regular screen later, but not having the full body visible would have been way more annoying!
What really sucks is all the vertical videos out there where vertical doesn’t make any sense, where horizontal would have made the scene fit better or where vertical simply does not add anything. People just holding the phone (wrong) and not thinking about it, eww. Maybe the phones should have the option to automatically record in landscape mode, regardless of the phone’s orientation? I have a third-party app that does that.