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.
Where do you think the heat comes from? Or where do you think the power that doesn't turn into heat goes?