By the same logic, you could strip away all the airbags, seatbelts, comfy seats and assistance systems of modern cars: After all, accidents still happen and safety mechanisms might even lure drivers into more reckless behavior. (This is in fact happening with seatbelts)
I think it's less useful to think about absolute safety than about which failures are likely to occur and how effective our measures against those specific failures are.
The --force flag is obviously not an effective measure against root deletions, otherwise we wouldn't have so many stories about it. My theory is that there are three reasons for it:
- As other people wrote, if you frequently batch-delete files, you get trained very quickly to always use -f as plain rm is very annoying to use for large sets of files. Unlike other flags, -f won't make you stop and think. This could be fixed by making rm-without-f actually useable - for example by only asking once and not for every file like, oh I don't know... Windows.
- rm can interact with shell parsing in very intransparent and fatal ways. My guess is that most root deletions happen similar to this post: not a literal rm -rf / but some unfortunate variable interpolations where the author didn't realize that they can evaluate to "/". That's a very unobvious point of failure that takes a lot longer to learn than just using rm. Therefore rm should absolutely warn about it.
- there is actually an expectation that rm could be safe as most deletes you do on a modern system are reversible - either because you have a " recycle bin" or a backup. So a warning would make sense to counter that expectation.