In principle, terrorists are terrorists, regardless where they operate or from which origin. I understand your point of view on the wrongdoings by the US in releasing those captured Xinjiang terrorists. There is no doubt that the US is terribly wrong to split the joint effort to fight international terrorist including those from Xinjiang simply because of its ideological differences with China. Well, China has every right to criticize the US for its wrongdoing, but should refrain from tit-for-tat retaliation by way of refusing to provide supply route for the international fight against terror in Afghanistan. I agree with you on that China obviously does not want to join the US and NATO in their war against Taliban forces, since this is not included in the UN mandate. Therefore, it is unwise and not advisable to send combat troops to join the war there. However, the fight against Bin Laden and his terror organisations is perfectly legitimate. Hence,  it is not tatally unacceptable to consider the request for a supply route to the Afghanistan Government and the US troops in Afghanistan.

As for the killings in war, it is indeed sad. But war is a continuation of politics, as the famous Prussian military strategist put it. According to the Chinese doctrine, warfare is classified as just and unjust war. A just war is, naturally, worth to fight, though it kills lhuman beings.