>>211704500
That's a garbage quote, Morrison. There's no need to explain why the crab sings because that movie simply presents a world where all sea creatures talk to each other and therefore obviously can sing. "Nobody pumps the tires" is wrong, somebody obviously does but it's just not important enough to show, the audience will automatically assume that someone is doing it off screen. That's like asking if Batman drinks water, you don't need to see him doing it to know that he does.
Why Superman has superpowers is a much more important question that needs answering, but the simple explanation that his alien physiology is charged by yellow sunlight is sufficient, there's no need to dwell on it further as the audience's suspension of disbelief will take care of the rest. Likewise, the secret identity only needs the explanation that Superman is a good enough actor to convincingly behave as two different people, combined with the fact that most people don't suspect Superman of having a secret identity because he doesn't wear a mask. That should be enough but if you really need more you can have a scene where Superman and Clark are seen together in public thanks to a shapeshifter or an illusionist or a robot. All have been used many times.