I asked my students the same question only last week. They had been bleating on about sport being good for people under oppressive regimes, and how the country would suddenly open up under the influx of sportsmen from far and wide, re China. They were not at all thrilled when I asked them why, then, SA had been ostracised for years. No satisfying answers, just some embarrassed faces. Racism again.
Governments only play politics with the Olympics when it suits their needs. If they abided by the notion that the Olympics were non-political the US and Russsia would not have backed out in the past. The IOC's choice for locations will always offend someone so it is a no win situation. People always use the big stage to try and press their political agendas which is pretty sad