I think many HN users tend to be Elon Musk fanboys because he (or at least his public persona) represents an idealized vision of what they wish they could be. He's fantastically wealthy, successful and driven, and he's working on "important" projects and Big Ideas. More to the point, he portrays himself as an engineer/visionary. Unlike other "heroic" figures in business (e.g. Steve Jobs, Richard Branson) Musk styles himself a builder, an engineer first and a businessman second, and so HN users who are primarily software engineers who maybe dream of starting a business see themselves in him.