His fictional biography putting him in his 50s, whereas the regular Superman is in his 30s is a meaningless point in this discussion, which was started by claiming that his status as 'the first superhero' meant he was deserving of some sort of respect from the company that this story is betraying.
It's rather a moot point, anyway - even if he WERE 'the first superhero' in any meaningful sense, that wouldn't mean he's any more deserving of 'respect' than any other fictional character.