I read the post. And this sentence: "Take stereotype person from every country and throw them in UFC cage. " makes it unclear, since it's talking about putting a person from every country and only one cage, which is why I considered the possibility that he wasn't talking about 1v1s after all. The fact that I considered both options means that I answered both hypothesis anyway, so I don't know what makes you so upset.
Just saying "stereotypes" is extremely vague, the stereotypes he's thinking about might or might not influence the outcome of a fight, hence why it's more likely to consider that it would be about who's the best fighter.
If it's not about who's the best fighter, but rather about what stereotyped attribute would favor the most a fighter, then it means that we're not concerned about the fighter's nationality but rather concerned about the fact that he possesses the said-attribute. In other words, he could be from whatever country, if he has the attribute that corresponds to a stereotype, it would do the trick, which means nationality is irrelevant.
Stereotypes do not represent the traits of people from a country anyway. They represent the distorted views people have on other people, which is a different thing.