It's Motorola's POLICY that says no APX 8000 sales to non-governmental agencies.
It's not any LAW that says that. Just Moto policy.
if you want an example of a radio where there IS a law that says that you as a civilian can't own it,
then that would be any radio with any form of Type 1 encryption in it. Encryptions bearing such names
as SAVILLE, PADSTONE, BATON, FIREFLY, SKIPJACK, GOODSPEED, etc...
Those, you can't have. If you are in posession of equipment containing such encryption technologies, you MIGHT be able to get a letter of authorization from the State Department to have it, but if not,
you'd be better off to wipe the radio clean of fingerprints, toss it in a box, and leave it at the doorstep of your local FBI office or drop it off at the front gate of a local military installation. (In that case, don't seal the box or they'll bomb squad it.)