Your claim appears to be "Rationality is winning." Therefore, if you're not winning you're not rational. Are you winning? [*] If not, are you not a rationalist?
The logic seems circular. You can say "I aspire to win and rationality is whatever gets me there", but that doesn't seem to define the pursuit in question at all.
[*] (This question is not "Can you quickly retcon your current state as 'winning'?")
You could be a really bad rationalist, or you could be not winning for other reasons.
Related to: Knowing About Biases Can Hurt People
HT: Marginal Revolution
Paper.