The parallells to Moses and Jesus are pretty clear. He's become a Christ Figure over the years, but lots of characters have been. He's kind of inherently a savior type figure, though he's not a literal messiah, other than to his own people occassionally in the comics.
1. Superman started in the Golden Age.
2. Superman has always had religious undertones. Look at his origin.
3. Superman being Christ-like has never undermined a need for a Justice League.
4. Superman's alien aspect is directly tied to the Christ metaphor.
I don't even understand where you're getting your ideas from, let alone how you were a fan of Superman's without seeing this stuff.