I have no problem with it. Those are the rules. I think it's fair payback for someone winning a medal for Team USA. In theory, it also lets an athlete know they are going to worlds and not have to peak once for USAs and again for Worlds.
Every year, there are people who run because they have qualifying times, but know they have no realistic chance of making the team. Or have a qualifying time but they are injured and run anyway. This is no different. As long as you have qualified, you should run if you want.
Also, you cannot predict that Symmonds will not do as well or better as whoever you think he is bumping. Surprises do happen. Look at Christian Taylor in the 800 in 2008.
It also matters that for many athletes that their sponsor pays them something for running at nationals. I would not ask anyone to give up a payday by not running a race that they qualified for.