Some time ago there was dismay on Mastodon (and Pleroma ?) instances about data scraping. Before that happened there were privacy concerned people automatically deleting their own toots, limiting them for example to the latest toots for thirty days. With Lemmy things are different since Lemmy is a link aggregator rather than micro blogging, and Mastodon has boost option (Called replay with Pleroma ?). However deleting your older comments (but not posts) automatically would be really nice for privacy reasons.
To learn is to change. If you haven’t changed any of your opinions over the course of your life, then you haven’t learned anything.
That’s why most people can recall at least a couple extremely stupid things they did while they were younger that they would absolutely not do today.