Using an engine to learn chess is like using a calculator to learn mathematics.
True. Hopefully, he's only using the engine to spot blunders. He still needs to learn from the traditional sources: books, DVDs, trainers, stronger opponents, etc. (And lots of self-analysis via blood, sweat, and tears...)
said the beginner with extreme authority
...with extreme authority? No, it's just my opinion; If you want to disagree, that's fine. BTW, I AM a patzer, but not really a beginner.
… Using an engine to study openings is a waste of your study time and effort. If you're using them just to see how to play against bad lines as you say, and you enjoy it then it doesn't matter. But your question also illustrates why you should not use an engines for openings, or study openings right now. Engines do not explain "why"
Isn't it possible that an engine can, in some cases, indirectly explain, by showing how it would play a position? Possibly instructive to see how an engine would continue after
?