[wizofaus]

I'm not I entirely agree that frequently witnessing racial diversity in movies isn't going to affect the way you react to what you might see in your own neighbourhood. Our perceptions of what's "normal" absolutely are shaped by cultural norms and they can be spread by literature, TV and film as much as they can by lived experience. I'm a bit baffled by your description of a group of friends from "every nationality that exists" but all being white skinned - how on earth does that even happen? FWIW I'm not American but I have grown up surrounded by friends and colleagues from all over the world, and they very much do have a variety of skin colours, eye colours/shapes, and other superficial features that mark them as coming from various ethnic/racial backgrounds. There's literally no racial appearance it would be at all surprising to see featured among those in my suburb (e.g. there's a significant population of Somalians, who have very distinctive features, but plenty with an obviously Mediterranean background, likewise Chinese, Vietnamese, subcontinental etc. among a slight majority from the more obviously northern European ancestry that I share). I certainly would have found the experience of going to, e.g. Japan and seeing almost nothing but ethnic Japanese quite unnerving if I hadn't had some exposure to that reality via TV and/or movies beforehand. When I do watch movies or TV shows made in the US that somehow manage to avoid casting anyone who isn't white in a substantial role it's hard not imagine that somehow the producers/casting agents felt uncomfortable about living in a multi-racial world and were subconsciously trying to project a world that only existed in their imaginations.