So. You can push down on it…
So. You can push down on it 1000 pounds as long as you don't try to torque it downward. The longer your lever-arm, the less weight it will tolerate.
The trailer hitch is maybe 8 inches past the pin. 4 bicycle rack is, say, 32 inches. 4 times longer so 4 times less load.
Looking at the table and the mount would let us figure out the rating for any length.