The reasoning for that was to prevent reducto ad absurdum and "It's YOUR fault". "You should have KNOWN that erudite command was going to fail." "You should h

The reasoning for that was to prevent reducto ad absurdum and "It's YOUR fault". "You should have KNOWN that erudite command was going to fail." "You should have known that our one-off program had issues you did not account for." "You should have known that the backups were not properly tested elsewhere for known good state." "You should have ....." In reality, some disasters were caused by idiotic things like "rm -rf /opt/somedir ." You just hosed the system, or a large part of it quickly. And we could say that your malfeasance of including the "." started wiping / immediately. But we can also say that rm should be aliased to prevent accidents like that, or that rm should do some minimalistic sanity checking on critical directories before executing them. People can, and will mess up. These computers are nice, in that they can have logic that can self-correct, or at least loudly alert errors.