"[You should] make the flames match the amount of wood in the bonfire..." - Yu Suzuki to his devteam in Shenmue's development. With such guidelines we must assume nothing was made "just because".
I always felt Ryo like a more calm version of Tao Lung from Way of The Dragon. A martial arts pumpkin, physical,
not dumb nor a good student neither, pure at heart so VERY naive (God, the travel agency part...)
So Ryo spend time helping cats, children and semiblind grandmas, but if you happen to be a bancho, sailor, biker and mess with him... you find him.
Yes, S1 Ryo will always say he "don't have time for it" and will try to avoid conflict but, when this has ever stopped a bully instead of encouraging him? He will continue to pick on Ryo and then Ryo picks on him. There's a moment he goes "Ok I gave you a chance. You dont leave me alone, you are going to pay. No mercy".
The band aid tell us visually from the very beggining "This guy doesn't joke". And he doesn't joke... ever (well, does calling FangMei "neko" count as Ryo's joke? I think he probably is naively telling his truth but.. that face and Aaahhh before throwing that at her XD)