Except that if a random citizen asked to search my person or bags I could refuse without being detained or prevented from traveling. The idea that the government is empowering you to search my bags but you are reporting your findings to law enforcement as a private citizen seems like a pretty weak argument to me. TSOs should be searching only for weapons, explosives, etc with a blanket rule that anything else they may find can't be reported to law enforcement or used as probable cause to justify a search by LEOs.