It’s not inconsistent at all, if you think it through it is quite logical although, as with much of the Laws, not necessarily written to show the logic.
A GK can never be disciplined for handling the ball in the PA if what makes it an offense is the handling.
On a restart double-touch, the offense isn’t related at all to the use of the hands, but touching the ball a second time (with any part of the body). As I posted above, it removed the oddity that a GK could be cautioned or sent off for a second touch with the foot that stopped a promising attack or was DOGSO, but not if he managed to use his hand instead. That was never logical.
(The same logic goes to the new offense of throwing something at the ball. The sole reason it was needed was to get past the GK exemption for handling offenses in the PA. Prior to the change, if a field player through a water bottle at the ball to stop the ball from going over the goal line, it was DOGSO-H and a PK, but if the GK did, you could get him for USB, but not DOGSO or a PK.)