I suspect that it is hardware programmed to do so by DJI for use with DJI Fly for our convenience. It isn't intended to be used as an Android tablet for other purposes than flying with the
M3 and
Air 2S, and associated actions. Unlikely you can override that.
Better question is why you would want to avoid it loading automatically? You can keep swiping up on the bottom of the screen from the Fly app while it is loading to return to the Android Home Page within seconds anyway. I'm sure you can also unload it from there, too, if necessary.