Huh, I don't really feel defensive at all. I simply don't feel the need to justify computer science as a discipline or software development as a profession. I originally came into college as a physics major and am doing theoretical computer science (math) as a depth focus in my major. These are generally thought of as the "hard" fields -- but I don't find any of them harder than computer science. Computer science just doesn't strike me as a field that needs defending. If it were easy there wouldn't be so few good practicing it.