Why don't you tell the full story?
Why was the army there in the first place?
Protesters were peacefully protesting for days until the army came and started shooting. (Deng want the protests to end quickly since world media was in Beijing and he didn't want the world to see what was going on)
But that is not even the point.
You keep ignored the fact that Chinese people protest against the government, army is brought out and then used to kill them.
When people "protest" against Japan, not a single troop is found....