I understand the sentiment, but if it's coming from a reputable source I'd disagree. I think it's ideal to understand the commands, but most users occasionally need to do some things that they'll never learn what the commands do but they need to use them. It's like saying never to run an application you download from somewhere. Sure, ideally you don't unless you've read through the source-code and double checked it's the same thing, but no one's doing that.