I think part of it is belief, part of it is physics. Out here in where I am every other jackass drives a lifted pickup. I feel like part of this is because if you drive a sedan, no matter how well rated it is, if a lifted truck hits your above the trunk, the only thing in the way is the seats, glass, A,B,C pillars and your head (mostly seems to be air) versus the more "crumple zone" you have in a taller vehicle with trunk, seats, vehicle transmission (still mostly air but I digress).
In a higher SUV, the chance of you getting hit in the head is less because it is higher. The only time I've seen it really make a difference was versus a semi-trailer (ironically). And that guy would have probably been dead anyways. Basically he was distracted (texting) I think and he ran a red light and decapitated himself under it. I guess that's the only time you'd want a lower car, but it more or less was a moot issue.