Bethany also weighed in on the topic in 2016 over at Graph Paper Diaries. She had discovered it, she thinks from Chuck Klosterman, and passed it along to me. The Tim Tebow Fallacy
Her attempt at a formal definition is probably the best summary:
The tendency to increase the strength of a belief based on an incorrect perception that your viewpoint is underrepresented in the public discourseMy favorite anecdote is still the guys calling in on sports radio, staying on hold for 45 minutes in order to be able to spill their furious opinion "Tim. Tebow. Is not. An NFL quarterback! PERIOD!" and then hang up.