Cooking is a negligible amount of the gas use, but in warmer states gas networks will do rebate deals with developers to get gas appliances into new homes to keep the domestic networks expanding. There can be transmission loss in these networks and curbing demand for appliances (Via City regulation) stops them expanding.

Also, at least in my country, the network connection fee to the gas network is often higher than the gas used by appliances, (warm climate) and residential cooks don't realise they're subsidisng the cost of our business gas users.