I agree that identifying yourself with the label rationality in such a manner that it interferes with acutal clear thinking is a grievous failure mode that people should be warned against. But it still seems useful to have some sort of terminology to talk about clear thinking, and I can't think of a better candidate term than rationality. I must say that I can't help but find it odd that you link to "Keep Your Identity Small" in discussing this problem. Did you read the footnotes? Graham lists that which we would call rationality as one of the few things you should keep in your identity:

[2] There may be some things it's a net win to include in your identity. For example, being a scientist. But arguably that is more of a placeholder than an actual label—like putting NMI on a form that asks for your middle initial—because it doesn't commit you to believing anything in particular. A scientist isn't committed to believing in natural selection in the same way a bibilical literalist is committed to rejecting it. All he's committed to is following the evidence wherever it leads.

Considering yourself a scientist is equivalent to putting a sign in a cupboard saying "this cupboard must be kept empty." Yes, strictly speaking, you're putting something in the cupboard, but not in the ordinary sense.

Graham says scientist where I would say aspiring rationalist, but it's essentially the same idea: believe true things, and use this true knowledge to do the best things, whatever they may be. Eliezer's "Twelve Virtues" contain the same warning as yours and Graham's:

How can you improve your conception of rationality? Not by saying to yourself, “It is my duty to be rational.” By this you only enshrine your mistaken conception. Perhaps your conception of rationality is that it is rational to believe the words of the Great Teacher, and the Great Teacher says, “The sky is green,” and you look up at the sky and see blue. If you think: “It may look like the sky is blue, but rationality is to believe the words of the Great Teacher,” you lose a chance to discover your mistake.

Do not ask whether it is “the Way” to do this or that. Ask whether the sky is blue or green. If you speak overmuch of the Way you will not attain it.

You may try to name the highest principle with names such as “the map that reflects the territory” or “experience of success and failure” or “Bayesian decision theory”. But perhaps you describe incorrectly the nameless virtue. How will you discover your mistake? Not by comparing your description to itself, but by comparing it to that which you did not name.

I do find it useful to self-identify as an aspiring rationalist, rather than simply as a rationalist, to disclaim any implications of having achieved some grand end state of rationality. I know that I'm still wrong---just hopefully less so than previously.