I suspect this inability to simply ignore inconvenient data is the reason for my low rate of rationalization.
This seems wrong, rationalizing is what you do to inconvenient data instead of ignoring it.
Speaking for myself, I think that rationalizing does typically (always?) involve ignoring something. Not ignoring the first piece of inconvenient data, necessarily, but the horrible inelegance of my ad-hoc auxiliary hypotheses, or such.
Anna Salamon and I are confused. Both of us notice ourselves rationalizing on pretty much a daily basis and have to apply techniques like the Litany of Tarski pretty regularly. But in several of our test sessions for teaching rationality, a handful of people report never rationalizing and seem to have little clue what Tarski is for. They don't relate to any examples we give, whether fictitious or actual personal examples from our lives. Some of these people show signs of being rather high-level rationalists overall, although some don't.