You know why they “tombstone”? (By the way, they don’t replace with a tombstone marker but instead add the marker.)
Because if you “accidentally” deleted something and then decided you wanted it back, you’d get really mad if they couldn’t do that. If they immediately deleted it, you couldn’t ever get it back
The copies and deep copies are for a similar reason: Some engineer accidentally deletes a bunch of data, it’s really nice to have a backup so you don’t lose everything.
Your second point is really difficult for me as a parent with a new kid. Feels like we “know” so much more about serial killers / bad things that happen to kids that we’re terrified of letting them do anything.
Of course in this case it would have been trivially solved by the city just adding sidewalks, but that feels like another point here.