i have no problem with them playing the back up players in the game after they had all ready wrapped up their spot. these are teams made up of players that are all very good and deserve a chance at getting on the field if possible. i do have a problem with not giving a full effort to win.
if i were a player and realized what the coach was doing, which shouldnt have been hard to figure out, i would have told him to gfy and played how i wanted or not at all. if i were a parent i think i would have told the coach my kid was done playing unless they changed their strategy and started to try and win.