The Tiananmen Square event was tragic, because of some lost of lives, but the authorities had to do something in the face of all the protesting. Otherwise China would have gone the way of the Soviet Union. It would have become a political mess.
Many of the people who took part in the protest movement at the time have admitted in hindsight that they were wrong. You need to be very open minded before you criticise the way a Government runs a country. China is a great nation and they are doing the best they can. China was totally right to do something about the protests.