I know Grados can have this defect, and the extensively modified Rega P3 turntable I use can contribute to the problemThe problem here is not the cartridge but the turntable. For unknown reasons Rega doesn't ground their motor and so it can inject hum into the cartridge- most often Grado gets the blame for this. I have placed a wire between the motor and the base of the arm, grounding the two together and solving the problem.
Its too bad there isn't more feedback about this issue!
Cartridges cannot be designed to favor classical music! The idea that any component can favor a certain genre is entirely mythological. Usually this idea is applied to speakers but it really doesn't matter- what makes a component good for one genre makes it good for another.