While it is true that class D amps in general emit radio frequency (RF) energy that can interfere with AM/FM frequency reception, class D amp designers are very well aware of this issue and typically make containing, controlling and attenuating these RF emissions a top priority in their designs.
If all class D amps were to be tested and ranked by RF emissions, however, I suspect the results would vary significantly between amps and that they'd also likely be directly related to the skill level of each amp's designer and the new retail price of each amp.
OTOH, I've purchased and used many stereo and monoblock class D amps in my system ranging in price between $630 and $2,200 and have never had AM/FM reception problems in my rooms with any of them.
Tim