You might as well ask why the Chinese didn't chase off their emperor earlier instead of waiting for the Revolution of 1911?Why didn't they seek for democracy under British rule?
Different times have different situations. What appears normal and acceptable today will be looked at differently by tomorrow. But what matters is how one tries to understand the situation and the driving forces / agendas behind the people.
I admit I am not familiar with the situation there. I don't judge what happens, I just hope that they find a peaceful solution. 25 years ago Germany had its peaceful revolution, leading to the reunification of Germany after 40 years of separation and Cold War - without a single casualty. It were the people on the streets who started the revolution, people showing their dissatisfaction with the government.