plawolf
Lieutenant General
It could possibly be because China has more interests both security and economically related in the Middle East and Africa, and with the rise of terrorism in both those regions and as Chinese interests come under increasing danger from terror organizations, China might think that it may eventually has to respond with force, and since both regions are a very desert environment, it wouldn't really make sense to deploy armored vehicles with tropical camo.
But this is just my best educated guess.
Middle East is a little too far, without bases and secure supply lines, trying to field a large land army in hostile territory is a recipe for disaster. Just look at Iraq and Afghanistan.
No, look closer to home.
What is the biggest, most significant and ambitious project China has ever committed to? Which just happens to involve building a comprehensive land based logistical, transport and communications corridor through some pretty unstable and dangerous countries and regions on earth?
China would not have committed such vast sums of money, resources, political capital, and pinned the hopes of the future of China's economic growth and development on such a project without putting in place real, tangible, solid security contingency plans to protect that investment.