There we a huge number of people involved on both the PLA and protestor sides. There are some reports which claim thousands of people killed and gruesomely disposed of; those people must have had relatives. We (outsiders and history in general) have very little idea what happened, and a single photo which escaped the censorship.
If the gunpoint forgetting is maintained for the lifetimes of the surviving participants, we may never know what happened.
Of course, even in incidents which are hugely documented, there is scope for denialists and propagandists to sneak in misinformation.
Edit: well, looks like there's lots more. I've been misled myself by how prevalent the Tank Man photo is compared to all the other footage!