I don't buy the whole sport vs sd thing. Either you can stop someone from effectively attacking you and attack them or you cannot. Motobu was able to utilize his karate in a "sport" environment against a pro boxer. I guess no one told him karate is not effective if used in this way.

What! Where to start.

It surely depends on the nature of the sport. You see no difference between Olympic tae kwon do and SD? Don't buy in to that?

SD training tends to focus on common assaults and how to deal with and avoid them.

MMA as a sport deals with dual fighting at all ranges, therefore self-defence skills are a by-product of the training. I don't see that a by product of self defence training is MMA sport fighting ability.

Yes Motobu beat a boxer, under what rules? Who was this boxer? How did he win?

Might it be considered as clutching at straws if the examples you use to support argument to be from the early 1900's in some obscure event?
"Its only pain, it wont hurt you"