Those IP addresses are just being assigned to their own networking equipment. Cox using the CGNAT network for that would be just as wrong as you using it. There's absolutely nothing wrong with Cox using private address space internally. If anything, there's something wrong with routing requests to private address space out your WAN in the first place.
What Cox is doing is completely appropriate and what AT&T and Cisco are doing is squatting on someone else's IP assignments.
What Cox is doing is completely appropriate and what AT&T and Cisco are doing is squatting on someone else's IP assignments.