Look, I don't work for Delta and as you can see if you look back at my posts, I am far from being an apologist. However, I have lived in ATL for 15 years and have seen how this stuff plays out. For the most part, the forecasts look terrible a few days ahead of time and then theres a last minute change which makes the weather a non-issue. A classic example: On January 8, 2018, a terrible storm was predicted. Complicating this, the College Football National Championship was scheduled to be played here. Everything was cancelled... schools, government, private businesses, and even the hospitals shut down. The forecast the night before looked a lot like the one for today... the next day it was in the 40s and partly cloudy.
Check out this newspaper article from the day before... sounds pretty dire, right?
The storm today exceeded the forecast. I live in a 2" zone and we've had 4" plus another 1/4-1/2" of ice on top. The weather came hours earlier than forecast. And the lack of precipitation at my house for the past 4 hours was also not forecast... in fact, the news all day has been saying that freezing rain will be back any minute... and it hasn't come back.
ATL services approximately 286,000 passengers a day. What are you suggesting? Cancel all flights for a whole day and tell those 286,000 people that they need to live with it? Or should DL give a waiver for people who don't want to deal with it, and try to fly planes to the best extent possible? Especially knowing that the original forecast was for 1-2" at most spread out over 12+ hours.