There actually IS output from the command on your screen print
Code:
C:3 D:3 E:3 G:3 H:5 I:3
and I think your Kindle is drive I: (at least it was in one of your screen shots).
So for some reason, Windows 10 does not seem to set the REMOVABLE attribute for your Kindle (and from other threads, Kobo's).
I think this should let Kovid find a work-around