I believe you are spot on regarding perception and and possibly an uncanny valley effect.
In my opinion, when our heads move we experience motion blur, our eyes cannot be focused perfectly when in motion (when the head moves slowly focus can track, but if the objects in the field of vision vary significantly in distance from the subject then a lot of refocus is going on). Only when we stop do we get full clarity in our primary field of vision and improved peripheral vision (I'm just spit balling here, outside my realm of knowledge...).
Games have started adding motion blur as an option, The Forest is my primary example. Turning quickly to find an attacker isn't just turning, it's perceiving the blur. In game it is creepy. Try turning quickly (first person shooter speed) to find a small object. This is perfect gaming realism, not uncanny at all (scary when being attacked, scary game).
24 frames per second for a movie provides a slight blur. Higher, well focused scenes, will be lacking in this some. I'm not sure if it is just the fact that we expect a movie to look as it does at 24 fps (prior experience) or if we find it uncanny. There is a softness to 24 fps as well.
Movies like Avatar are perfectly focused and should be uncanny, but they are like video games without motion blur (Avatar used motion blur a lot though), perfect focus at all times. They are realistic, but not of our reality. Uncanny? Yes. Are we comfortable watching it? Yes.
During the trash avalanche scenes at the beginning of Idiocracy I noticed the entire frame was in perfect focus (the far off background). I only noticed this after a couple of dozen viewings...
Anyway, very thought provoking comment.