It really doesn't matter that much. 250km flat stages are not hard for the riders at all. Riders do under 200W in the peloton for 1 full exta hour boo hooDo you really think it was Adam Hansen who didn't want to do the stage ? He was merely the UCI rider's representative at the Giro and did the negotiations with the organisers on behalf of the riders. Anyway, hopefully, RCS have learned it is silly to have a pan-flat 250+ stage in stage 18 or 19 - Actually it's silly to have this type of stage full-stop.
It's really about the precedent. Riders don't want to race in the rain so they flatout refuse to race the parcours set out by the organiser? Please.