The Uighurs are actually the largest ethnic group in Xinjiang. Members of other ethnic groups, including the Kazakhs, the Kyrgyz and the Hui, are fewer in number and represent no more than 1% or 2% of Xinjiang's minority population. That is why we hear about them a little less. However, these issues have been addressed by Kazakh and Kyrgyz activists in Kazakhstan and Kyrgyzstan.
The problem is that the governments of these central Asian countries cannot stand up to China. In fact, they cannot openly criticize China because they are very dependent on economic relations with the People's Republic of China. Therefore, we hear much less about them, and that is unfortunate. Since the Uighurs have suffered more and are greater in number, we hear more about them. It is important to add that the Uighurs are not the only ones affected; all Muslim minorities in Xinjiang are.