It is okay for a guy to shave his legs. Many men who are swimmers, body builders and models typically shave their legs before a competition, according to Men's Fitness.
Swimmers shave not only their legs, but also their arms. Hair creates a drag in the water, which slows swimmers down. A cyclist shaves his legs for medical reasons. If he crashes and has a bad case of road rash, the hair could get caught in the scabs and make it harder to treat the wounds.
Models and bodybuilders like to have a clean look for photo shoots and competitions. They want attention on themselves, not all the hair.