Its true you may not get to choose your household electricity source. But that doesn't give you free pass to start consuming as many kilowatts as you want. We make choices with what we consume. You don't get to buy clothes made from slave labour and claim you had nothing to do with it.
I don't get to leave my car idling 24/7, burning gasoline and spitting out toxic fumes. It can't be morally justified with "well I paid for it, mind your own business, go lobby the government to make a law against leaving my car on 24/7".