That's because you are ignorant of radio frequency technology, circa 1940. The only reason a shared frequency band like 2.4 GHz works at all is because we have invented technology that can implicitly synchronize with other senders through avoiding collisions with ongoing transmissions, e.g. through CSMA/CA. Obviously a band like 2.4 GHz will simply not work if devices were allowed to transmit permanently like an analog radio. And so out of simple necessity the regulation for shared bands has very broad language to the effect that you can not interfere in any way with others operating on the same band.