They have poorly working brains. Zen 5 is Ryzen 7, Zen 4 is Ryzen 6. Their names are a mess.
Architecture generation versus product generation. Zen 4 is the fourth generation architecture, Zen 5 is the fifth generation architecture. The product names are never consistent with architecture or else Intel's "14th Gen" would actually be 5th gen (Sandy/Ivy, Haswell/Devil's Canyon/Broadwell, Skylake/Kaby/Coffee/Comet/Cascade Lake, Ice/Rocket/Tiger Lake, Alder/Raptor Lake).