I don't agree with that at all; a web browser has easily a more complex user interface than a single-purpose command-line tool like “rm” – and that is even before we open any document at all, with all their conventions we have to learn before we can effectively navigate them.

Everything has a learning curve, of course, but are you sure you're just not much more familiar with one of these two?

(edit: just to clarify, what do you expect a decent rm to do when given a single argument of “-”? While there may still be systems where that does not do what you'd expect it to do – it's no different to existing obsolete versions of browsers that do nothing at all when you type in something other than a valid URL in the address bar – and are thus considerably harder to use for some not familiar with the technology. The harder corner case would be to try and remove a file with name that can be confused for a valid flag – like '-i' – but even then, that's about the only corner case for the tool, and not a steep step to learn. Any recent coreutils rm will even suggest a valid command to remove files that look like options, but are not actually valid options, so some thought has been given to discoverability as well.)