Why should firefighters fight house fires because house fires are never ending, right?
Why should cops investigate homicides because homicides are never ending, right?
Why should soldiers fight in wars because wars are never ending, right?
Why should doctors treat the sick because people getting sick is never ending, right?
Talk about taking one point and making a big deal out of it..
You want to talk about it, fine?
Superman have to make this sort of decisions every time, every moment. Because at any point, there are millions of people who need some sort of help.
But, who to choose? Superman can't be everywhere. And he's not as fast as Flash (heck, even Flash can't save everyone).
But, that is the sort of thing a lot of writers/creatives just ignore...instead they write bland stories about Superman beating up villains.
(Granted there are good ones among those too).
The best Superman stories are where he has to deal with such things, for instance - Peace on Earth, where he tries to solve World Hunger.
Or Kingdom Come, where his generation has inspired a more violent class of superheroes (and he has to deal with that).
Every time Superman chooses to save someone, he's also choosing to not to save someone else (well, millions of others).
And the whole Clark Kent persona - he could actually devote all of his time for heroics and save even more people.
But, you don't see him doing that. I don't count that against him. Because Superman isn't a god. He's an individual. He may have the powers of a god, but he isn't one. He's a good man who has the capacity to do great things, and does those things.