Because as far as I can find, the protests were nonviolent until the army was sent in to clear the square. When protestors blocked the army a standoff ensued, which was eventually forcefully broken as per the CCP’s orders.

The people in the square left peacefully and without the use of violence. There was no “standoff” in the square. The violence occurred in other neighborhoods, not in the square itself. You can find contemporaneous Western media coverage confirming this, because there were a lot of Western media there at the time. It’s well documented. That’s why we say that the “Tiananmen square massacre” is a myth, because it wasn’t in Tiananmen square and it wasn’t a “massacre.” The military didn’t kettle peaceful protesters into a square and indiscriminately mow them down and crush them under tanks.