Tiananmen Square was apparently not a massacre of thousands of unarmed civilian student protestors,

Actually, that one is true, you can look it up on wikipedia (including plenty of reliable sources): The massacring was in side streets while the main protest on the square was dissolved "peacefully" by telling students "well, you can go, or we also have rifles here".

The whole thing was flanked by a power struggle within the CCP between reformers wanting to work with the students and hardliners, who ultimately won out but didn't go so far as massacring the students without giving them a chance to cave in and leave on their own. They wanted obedience, after all, not blood. And, culturally speaking, obedience is what they got out of it there has been no popular questioning of the overarching party line since then. Localised protests for or against local issues, sure, and even plenty of them and that's tolerated but nothing that could shake the system, and most of all it's not movements. The CCP is very keen on there being no movements but their own.