Every culture decides how to remember. Whether to remember at all. Who to remember and for how long. Each society develops its own devices for praising and blaming, extolling and denouncing individuals, behaviours and ideas.
Unremembering is not the same as forgetting. Forgetting leaves a void in the record, unremembering marks the memory for removal, leaving a trail behind. This trail is one of the many ways cultures invest in their future. Oblivion forces us to start from scratch. Unremembering has something to say about the past and seeks to impart a lesson or some wisdom.
Not every act of unremembering is wise, though. Authoritative societies, old and new, usually wish to turn unremembering into oblivion, which is just cultural death. From ancient Roman to the Soviet Union, unremembering has been one of the weapons societies used to control the past, each time differently and with different results.
The past is what we make of it, depending on what we choose to remember, to unremember and to condemn to oblivion.
Cultures remember more than individuals ever could. One could even say that a culture is nothing but a texture of memories, a fabric of rememberings. And each of us is weaving it every day for everyone else.