I do not understand the merit to the reasoning of this question. 2008 has long passed us and the Olympics in China are no longer really in talks since we are already talking about the 2014 Olympics in Russia. Well Tibet may continue to be an issue we can go about talking this differently.
No, China's actions in Tibet have not been abusive to the extent that a country should boycott the 2008 Olympics. China will shine on the international stage. The United States works with China on economic issues, and it would look like the United States is picking and choosing where to take a stand if the United States decides to boycott the Olympics.