Like the title says, I always wondered why, when you select "imperial" measurements for everything, is RTH altitude always in meters? Been that way since I've been flying and has never been changed. Goofy?

No reason ... that's just how it is.
It's like why the manual has hardly been improved or why RTH just lands if iniated within 20 metres..

Goofy, no.  Annoying, yes that I have to do a quick multiplication by 3 to get a ballpark altitude.

Agreed, if everything is in feet, so should be these settings...  all it is, is a little tweak to the app.. the only reason i can think of, is that some of such numbers get transmitted into the DJI, and stay there in case of signal loss - perhaps the actual aircraft deals with meters only? but if so, then the app should do the conversion before sending the data over. Certainly does seem a bit..  not finished up all the way.
On the same venue, when you have your go app set to metric, is your speed in kph or is it in m/s? Sll the speeds are certainly in mph if set to imperial, vs say ft/, or ft/s, which I think is actually a good thing.