>>213934562
This is a noble sounding line, and Lex says it because it sounds noble, but Lex Luther is also a narcissist in the actual mythical sense of the word.
I.E., Narcissus did not drown because he saw a hot guy in his reflection and tried to fuck it, Narcissus drowned because he saw the beauty of his own reflection, and could not differentiate himself from it. Luther cannot distinguish between "Humanity" and "Lex Luthor," he doesn't even consider that it's objectively good that Superman is saving people, and he doesn't actually want a human child to look up to a Firefighter, or that the existence of Superman exposes and defines the limitations of humanity.
What Luther is actually upset about is that the human child will not be looking up to Lex Luthor, and that Superman exposes and defines the limitations of Lex Luthor, and he is furious that without Superman, HE would be the greatest being on Earth, and with Superman in place he cannot be, no matter what he actually does. Rather than seek ways to become greater than Superman, he instead expends enormous effort trying to destroy Superman, thus revealing his talk of potential and human achievement as a cope to disguise his own insecurity.
The point that he makes is actually insane if you say it not in some philosophic high-minded way, but in the context of thousands or millions of people being killed by disasters that Superman has prevented.