In one of the last episodes from the prior season, she's walking around Winterfell with an underling, and specifically discussing the amount of food supplies they have, noting that it isn't enough, and directing that actions be taken to get more. That's before she knows that all those other forces are coming.
So it had been established long before Danaerys arrived that Sansa was directly involved in, and very concerned about, having enough food to feed everyone there.
Maybe she liked making that point for other reasons, but it also was a very legitimate concern of hers, and honestly a very valid point that neither Jon nor Danaerys even attempted to answer.