About a week ago, on the Dirty into Atlanta. ATC says new atis "Dixie" is out and one of our finest comments that "shouldn't that be delta" ATC says it's interchangeable in Atlanta they use both. Tool says "It's only to be used on the ground in reference to gate or taxiway designations" ATC again, and to his credit with a laugh says " we can and do use either here because of all the Delta flights and mentions that you must not fly in here much". Capt tool gets more testy and goes into the "I've been flying out of here for 24 years and this is the first time I've heard it on approach control" where as the controller laughs and says "now you have, contact 124.6, good day". Guaranteed this capt tool had long sleeves!