That's not the point. I love Uncle Ben as a character, and I think he's a perfectly fine person to say the line, but I never said it needed to be him. In the original comic, it's just something Peter realises on his own because of the death of Uncle Ben, which works just as well, if not better than him being taught by someone.
The point is that, regardless of who delivers the speech, (Ben in TASM and Peter in Civil War), they butcher it by finding some roundabout way of saying it instead of using the concise and iconic line that has stood the test of time so well. It's stupid.
Also, if you think a person needs to be "super" to understand that, with great power, comes great responsibility, you've missed the point entirely.