I would suspect that post-edits are stored as deltas instead of overwriting originals anyway, so not much point randomizing them if you don't trust the company

I would suspect that post-edits are stored as deltas instead of overwriting originals anyway, so not much point randomizing them if you don't trust the company to delete accounts. On a system I worked on every comment (or comment update) was a unique event. Only the latest was kept for immediate retrieval but I could pull up all events from cold storage if needed for special purposes.