I tend to think China invaded Tibet purely for purposes of national security.
Few recognise or empathise with recent Chinese history and the brutal European & Japanese invasions and interference.
Thus, when the Chinese were finally free post WWII, clearly their insecurities and experiences lead them to secure their borders as much as possible.
Further, that Tibet was a backwards feudal hierarchical religous state based on slavery did not help their cause in the face of a idealistic communist renaissance.
French political cartoon from the late 1890s. A pie representing China and is being divided between UK, Germany, Russia, France and Japan.
