I think it is perceptual but not that specific to the medium. A faster frame rate “feels” closer to reality and the 24fps frame rate is far enough from reality that it’s easier to perceive as “something else” which allows fiction or dramatic content to be perceived differently. I tend to agree with that conception of it. The idea that when the frame rate gets high enough to not be noticeable then the brain treats it more as a real world perception and the standard is higher so it is more harshly judged and ends up seeming as lower quality reality instead of fantasy mode.