Because lazy and busy.
6th DesDiv enters a curry cooking competition to decide whose dish will be served for the next year. After much trial and error, they overcome their differences with a helpful word from Nagato. With the other competitors taking themselves out, 6th DesDiv goes against Ashigara and Haguro, and win. Mainly because Nagato can’t stand spicy food and 6th DesDiv’s curry was mild.
I can’t be bothered at the moment.