Y did they make kids fight Hako & Zabuza? Shukaku? Sound Four? Kimimaro? Itachi? Kabuto? I could keep going but the point is even in our world 'Fair Fight' is an artificial, unnatural, and unrealistic concept. Kids fight adults, n vice versa, because when it comes to survival it doesnt matter your years, fitness, or experience EVERYONE present/available must either Fight or Die, cuz Flight is no longer viable option.