I'm happy that people do leave early, if everyone left bang on the whistle it would be a nightmare getting out.
In any case what about the ones who rush to get their burgers, pies and beers 5-10 min before half time? Is that any different? As soon as Wed scored there was a mass exodus for food.
If everybody left at the same time it would take even longer to get home. The early leavers actually do a favour to everyone who stays until the end, so I wouldn't knock them too much.