I think a valid interpretation of GPs point could be that top-level folders should have special properties so that they're not at risk of a bad rm, e.g. xattr "unchangeable" flags.
The fact that you can accidentally nuke the system seems a remnant from the olden days which we should have corrected a long time ago.
(I think GNU did a valid mitigation with preserve-root, just musing philosophically.)
That's reasonable, I was mainly responding to this part
> Being special to just / doesn't make sense to me.
and explaining why being special to / can make sense. I too often feel like people see comments like that and decide to let perfect get in the way of better in their own work.
"immutable" top-level folders won't cut it. In order to recursively delete a folder, rm has to delete leaves first. So, you will endup with empty top-level folders, which is no better.
>rm has to delete leaves first
There is nothing fundamental with rm for it to work like that.
It does if you ever want rmdir to succeed.
I think they mean that rm could check the folder you're trying to delete and see if it has whatever attribute and if so don't delete it's contents. so "rm -rf /" would see that '/' has it and be a no-op, but '~/home/foo' doesn't so it would recurse and start deleting. It could go further do that check for each sub directory recursively, so say '~/home/foo/bar/baz' that 'bar' does have the flag so `rm -rf ~/home/foo/` would delete everything else from the foo folder but leave bar and it's descendants alone.
> … GPs point …
I'm slightly disoriented, who's the other GP?
(I'm a GP.)