Motion in Vi is based on treating the home row of the keyboard as arrow keys. H, J, K, and L are left, down, up, and right. They aren't mnemonics, and so scrambling them around (Dvorak) is just doubly confusing.

Oh, huh, never considered that a real issue. I've used Vim on Dvorak for years, and use hljk for motion.

It's nice that jk are adjacent on Dvorak, and hl are conveniently placed as well.

Can confirm, I use Dvorak and vim without issues. I find myself not using hjkl very often though, since I can usually use another movement to get where I want to go, so it's really not an issue.