I run forums and have done for +20y.
Reddit may have a user agreement that allows them to use the data forever, but historical versions that were not visible (effectively soft-deleted on edit) puts this into a risk area as it removes the ability for someone to control the data thus transferring ownership far more explicitly to Reddit.
Reddit should be very cautious here... you only get a lot of protections (EU eCommerce Act, etc) but being mere conduit. Arguably volunteer moderators took on a lot of the liability by their act of moderating, and Reddit were able to distance themselves from a lot of the content on the platform.
But once Reddit go intervening in the content, choosing to make some old revisions public, they're now taking editorial decisions that strip them of a lot of the things that protect them.
This is an incredibly naive move in the big picture.