you’re supposed to wash cast iron with water, then soap then water again. then you dry, put it on a hot stove, and once all the water evaporates away, you rub it down with some oil on a cloth/paper towel, and get that real hot. then you can turn off the heat, and wipe off excess oil before putting it away. It’s not as straightforward as just tossing it into the dishwasher, but it’s not as complicated as some would have you believe. also, you can wash cast iron. soap doesn’t hurt it.