The requirement to "accept interference" is legal rather than technical. It means that if the device experiences issues with interference you can't use the normally available method of filing an FCC complaint to get the source of the interfrence shut down.
That seems weird to specify-- interference seems like an environmental hazard to be expected, like saying a light bulb must "accept" a brownout.
Does it mean "it won't be damaged by the expected level of RFI" or is there some sort of "active rejection of interference" they're explicitly forbidding?