I feel sympathy for the athletes and others who have to go there. I'd imagine a lot of those folks are rationalizing that they can stay safe and healthy; most people do set up some form of denial to deal with threats. It does seem that there is a percentage who've decided not to go, some with a well timed injury or another reason they chose not to be there.
Olympics as a massive endeavor where all these events happen same time, same place doesn't seem to be a real good concept with the realities of the modern world.. JMHO