AL, IN, LA, MO, SC, TN, and TX are all in the top half wrt population and states where Trump is underwater include NV, NM, IA, HI, NH, ME, DE and VT - all of which are in your bottom half wrt population. A state's population would appear to have little to no bearing on whether or not Trump has a net positive approval rating.

You may have "expected" the states where he has a net positive approval rating to have such, but if you did so in consideration of State populations, you're reasoning was (dare I say it - once again) flawed. ;0)