He cooked soba for some people and got incredibly pissed at the realization that the people who ate smile leftovers got the laughing side effects knowingly because they were starving.
But at the end of the day there wasn't anything else to be done to change the situation other than defeating the beasts pirates (most of the edible food in Wano was stockpiled at the flower capital and other beast pirate farms), which he was fully on board with of course.
Nothing is out of character for him, he just wasn't the focus of the arc obviously.
If anything what's weird is how Chopper hasn't tried curing the SMILE side effects