But Peter's creed essentially was that he must help others! The very first story featured him trying to use his powers for his own self-interest, and ignoring the robber because it wasn't in his self-interest to stop him. That taken without the consequences of Ben's death would've been perfectly cool by Rand!
Everything that happened after that was Peter growing away from that ideal toward some more humanistic, even altruistic, saving people not because he wants to or because it makes him feel good, but because he feels he has an obligation due to his amazing powers. His life was regularly poorer for it, even, to the point he would try to dump it on occasion, only to be pulled back in when he'd see someone who needed help, not because he wanted to help or helping them didn't ruin his life regularly, but again, compulsion.
Spider-Man is a shockingly anti-Objectivist character at his heart to have been co-created by Ditko. It's a funny sort of thing.