Can't really blame the airport authorities for not having de-icing fluid AND THE MEANS TO APPLY IT on hand; after all, how much of this kind of weather has Dallas experienced in the past 10, 20 years? That's a LOT of money to have to spend on equipment that you "might" need at "some time in the future".
The parallel might be drawn with fire-fighting equipment...how often is it needed? But of course, fire-fighting equipment is there to save lives, not to "expedite travel" which really has nothing to do with saving lives.
Perhaps in future the need for de-icing at airports in the southern US may grow... but in the meantime how many people are prepared to pay more for their tickets (and/or airport taxes) "just in case"?