I think that guests don't need more than a blanket information like that. Joomla doesn't handle it as 404, e.g. collects it in redirects. Admins can activate Debug for further investigations. In other words: I'm happy that there is just one simple error page instead of 15 variants in the background for this or that. Can create an override for my error page or just 1 language string and handle the output like I want instead of confusing people with blah blah concerning the reason why they don't see nothing.