thats one isolated example, which when compared to ALL combat sporting events and matches in history, is INSIGNIFICANT at best.   99.99999% of the time, people fight there own weight.  Hence why we have weight classess.   This isnt to say that a smaller guy, couldnt beat a bigger guy, as it has happeend many times....but overall bigger guys can get away with having less skill.   smaller guys cannot (unless there very very strong).