Those devices are all transmitting at low power, usually to a WiFi / cell base station nearby. The issue here is when several devices are transmitting on high p

Those devices are all transmitting at low power, usually to a WiFi / cell base station nearby. The issue here is when several devices are transmitting on high power at the same time. Also, a computer is a single shielded device with most data running on a single motherboard and a few cables. Avionics are well shielded, but the cables and antennas run the length of the airplane and there's a _lot_ of devices in a typical setup (ADF, VHF NAV/COM, GPS, TCAS/ADS-B to mention some, all of it duplicated for redundancy), so the chances of one of them being affected is a bit higher.