Growth isn't going to always be strong. Economic cycles are inevitable, even if they manage to kick the can of a correction down the road today, it will just come back worse in the future.

People in China can only express their discontent by rioting (which happens in China, a lot). They have no other real way of communicating with officials, they can't even make sneaky jokes on the internet anymore to express their dissatisfaction. That alone is a very dangerous situation.