They probably didn't know the service would go down. For that, you need to identify the minimal requirements for the service to be up upfront, and code that requirements into the UI upfront. Most tools don't do that. File managers don't check the file you delete is not necessary for any of the installed software packages to run. Shells don't check the file you overwriting doesn't contain vital config file. Firewall UIs don't check that this port you're closing isn't vital for some infrastructural service. It would be nice to have a benevolent omniscient God-like UI that would have foresight to check such things - but usually the way it works is that you know about these things after the first (if you're lucky) time it breaks.