It's easily disproved by the fact that they think they are escaping it by simply moving away from WiFi. The 2.4GHz band is swamped in most consumer settings by remote controls, doorbells, video systems, remote control cars.
Beyond that (imagining you somehow eliminated all of those) the biggest source of radio frequency garbage is going to be from space rather than a consumer grade <1W transmitter, the atmosphere is pretty opaque to 2.4GHz. Somewhat coincidentally the cosmic noise we can hear from earth is mostly in the microwave range.
Maybe if people's skulls started vibrating in time with the woodpecker [0] or something I'd believe it.