No one has ever beaten me. I have beaten Mall. Mall won against Novice. Novice won against oromagi. Oromagi won against RM. Between the 3 of them, Novice, oromagi, and RM have beaten at least half the users on the website. By the transitive property of debating, I am the best debater on the website.
And this is why the transitive property doesn't apply to competitions.