As I understand it, it's predominantly the noise that annoys people (At 110db up close, a turbine is equivalent to a propeller aircraft on taxi, and while most people hear the local town airport when the wind is in the right/wrong direction and/or there's a temperature inversion making the sound carry, those aircraft take off and are gone, while a turbine just keeps droning all day). ~60db has occasionally been measured near housing, and that's loud enough you'd have to raise your voice to talk -- not what people move to the countryside for, and as it's hard to get rid of a turbine after it's built they'll fight tooth and claw to stop it being built anywhere near them.