He's not making a case against Roshi, but against Dr. Gerowhat does oldness or strength have to do with anything in a fighting game?
he blew up both a mountain and the moon long before anyone did anything of that sort, and hes even the origin of the super buff transformation.
gag characters are a thing
you're also championing variety by having 17 because hes slim and has long hair, but apparently being old is bad