Because it was appropriate to set the facts straight when he was being promoted as a leader of the 1989 Tiananmen Movement. He wasn't, those were all students.
There are many more people in China who have done more to bring accountability and the rule of law to China than Liu did. He's been picked as a totem not because of what he represents to China but because of what he represents to the West.
Why didn't they pick Chai Ling, Wang Dan or Liu Gang instead?
Maybe it was related to their less than wholehearted embrace of 'western values' as a solution for China's ills?
You and the west can look at Liu more than the others.
But it doesn't change the fact that Liu went back to China and to write books about democracy and he paid the price for it, a fate both he and his wife were aware of likely to happen.
You're effort to marginalize him by such degree shows your pro-CCP troll agenda for one, and really pisses me off for another.