IMO it's to keep the country together. Super-large nations tend to promote separatist movements along its fringes. In the case of Russia and China they're held together with a strict regime. Other countries provide levels of autonomy on a more granular level. As a rule: monolithic = dictatorial. The moment they get true democracy in China will be the start of armed conflicts and calls for independence along the border regions. Again, just my opinion.
Except that in any "democratic vote" such a 'call for independence' would be voted down, as the number of Han chinese outnumber the ethnic minorities in those regions.
They've thought of that problem already.
True democracy... (Is that like a true scotsman? ... Who has a true democracy?)
