but I don't understand how I
So part of the national emergency system in the US is built around AM radio. The reason for this is the behavior of radio waves at these frequencies. If, for instance, some large fraction of all communication infrastructure were wiped out, a small number of powerful AM radio stations could, with their output power at maximum and during nighttime hours, cover the entire continent with a signal that can be received by very simple, very low power receivers. This is a basic property of AM radio that's been understood for a hundred years now and the basis for certain regulatory decisions, like maintaining a select set of special, geographically distributed, high power AM radio stations across the US.
Unfortunately for car makers, which are either actively pursuing or being pushed into electric products, high power electric motors and their power supplies are hard (read: expensive) to keep quiet: they make a lot of RF noise, especially around the same frequencies as AM radio. So, rather than innovate or pass on these costs, the car makers just figure the easiest (read: most profitable, lowest cost) thing to do is take a giant shit all over the RF spectrum while selling their 8,000 lbs electric tanks.