i don't think boycotts are necessarily a choice for the athletes involved...in 1980 a lot of british athletes went to moscow, and ignored thatcher who didn't want them to go
quite rightly so as well. The US made an absolute farce of those games by not turning up and persuading some of their allies not to go as well. As it was the British team, and several others, marched under the Olympic flag and all gold medals won by them were met with the Olympic anthem rather than the athlete's national anthem.
As usual, sportsmen and women were manipulated to make political points by politicians. Damned if they do and damned if they don't.
Iranian athletes are encouraged to withdraw if they ever find themselves in opposition to an Israeli one. That's bollocks as well.