It's sort of true, but not entirely. Yes, NBC is showing a lot of the sports the US excels at, but those are also sports (like basketball) that are hugely popular even if it isn't the Olympics. To me, it would be equivalent to US media commenting that European countries are airing mainly soccer/football.
Because the US averages 12 hours behind Beijing, it makes it difficult to watch much live save for the evening or early morning events. They are showing a wide variety of sports, but mostly by tape delay. You can watch quite a few events live streaming online, though.