This is basically every kid ever, if you think about it for longer than a half-second. This isn’t a Superman thing. It’s not profound. It’s just the human experience. It’s how we do. It’s not special.
To quote Orson Welles, “the right reading is the one I’m giving (and not David Brothers’)”. The “feeling like an outsider” part is, yes, typical of all children and indeed, many adults. But that’s not all the quote is about. Superman is a “true” outsider, as opposed to just feeling like one. He’s an alien, and he has to keep his distance to protect others from his powers. The trick is to mix the relatable aspect (we all feel out-of-place) with the different (real alien with powers).