I wouldn't mind quite so much if it was because the people filming that way believed it looked better. But the real reason is usually because they are too dumb to think of turning their phone on its side.
That's a little harsh but it does seem strange that when someone is a fan of a product they will refuse to acknowledge its flaws and will see every change, good or bad, as an improvement. Maybe I'm guilty of the same with the products that I like but Apple provides a lot of examples of this behaviour.
I have the Zenfone 8 Flip for the same reason. I also don't care about selfies but for people who do it's great because it uses the rear camera for selfies.
I'll never have a phone with that dumb notch til that's all that's available
'The quick brown fox jumped over the lazy dog' does not contain the letter S.