Stuff happens but runway incursions are a big deal. Clearly the DL300 crew was in error. The tower controller didnt help by adding the “whats your gate” question to a runway hold short. She could have let that unnecessary question to the ground controller who would have gotten them after crossing the runways.

The delta boy, unless the radio didnt pick up their transmission, may have fibbed a bit to the controller. That wont go good at FAA or ATL.