This proves that China don't understand Islam and muslim brotherhood. If infidels & anti-God people like China attacking muslim majority country like Indonesia, this will automatically be all about religion.
For muslims, war againts infidels attackers like China will automatically become a jihad, a holy war. Killing China in a holy war will be granted huge reward by God. On the other hand, if muslims die in a holy war against China, muslim souls will go straight to paradise/heaven as martyrs. Muslims believe that this is the best way to die.
There's a good example about this especially in relation between Indonesia and Pakistan. Back in Nov 1945 Indonesia fought in a huge war against the British and the British Indian troops in the coastal city of Surabaya. Suddenly the British Indian troops who were muslims (The Pakistanis) siding with Indonesia and fought the British. Most of them died in that war helping Indonesia. They didn't care that Indonesian troops and militias didn't have anything. They didn't care that British troops had everything from tanks, aircrafts, and warships. Why? Muslim brotherhood. They all died as martyrs (insya Allah).
So if China attack Indonesia now, all muslim fighters around the world will want to join the holy war and retaliate against China. Remember, Indonesia herself has more than 200 million muslims. China's attack will potentially generate the biggest number of muslim fighters around the world ever. Maybe even rival the muslim fighters from the crusade war era. Wanna try? Go on then.