He was no fan of sporting contests - but we're not talking about sporting contests, are we? The record is clear that both he and his students often took on people in other arts. That has nothing to do with aggressiveness or competitions.
I don't know, I'm not sure "taking on" someone is any different than a sporting event unless they were trying to kill each other which I'm sure they were not. I don't see how accepting a challenge from someone of another art could avoid being a competition. I don't know, maybe I'm wrong.
Was that activity pre or post war? I'm just curious.