The issue here is the frequency used plus power and spurious out of band emissions. 'FM Radio' (really 150KHz wide FM modulated 88-108Mhz) has propagation generally limited to line of sight, perhaps a few hundred miles at most due to earth curvature and the signals go off through the atmosphere into space so do not interfere with anything beyond the immediate range. FM also has good interference immunity due to the capture effect of FM signals so spurious emissions nearby are typically ignored.

2-25Mhz reflects off the atmosphere and returns to earth and the multiple allocated bands in the range are typically less then 6KHz for broadcast AM and other bands often <3KHz SSB down to 100Hz CW can be completely trashed with spurious emissions. 60, 80m and 160m can be difficult to use already due to all sorts of noise from notionally low power devices in the mW range on nearby, or sometimes nowhere near, frequencies. The wide range is probably to enable use regardless of the current maximum usable frequency (MUF) to ensure atmospheric reflection. MUF varies, sometimes considerably, by time of day, season etc. However the reflections do not stop when you receive the signal, they continue to skip and be received in many additional locations that are not the intended destination.

Someone pumping 20KW across the range could cause an incredible amount of disruption, essentially worldwide. See Ringway Manchester's great series of videos on the Russian Woodpecker (it was speculated in the MW power range) https://www.youtube.com/watch?v=wB_jiigRq-c