The thermal design power is the maximum amount of heat generated by a computer chip or component that the cooling system in a computer is designed to dissipate in typical operation. TDP =/= power consumed
I think he is trying to argue that TDP is a figure about the cooling requirement during peak power usage. Actual power usage may or may not be less during typical workload.
but TDP is also a function of power consumption, directly proportional. So comparing TDP of processors of similar fabrication should tell you about comparative power consumption if not the exact difference.
