For example, a company may practice test driven development (TDD), and may evaluate for a candidates ability and desire to use TDD as part of their engineering culture fit. TDD is not necessarily better than alternatives, and a candidate may not necessarily be better because they can do it. It might mean passing on better candidates who don’t prefer TDD.
Culture fit can cover many different aspects, and most are not about being past a “good enough” bar, but rather valuing the same things as the company. To “fail” a culture fit interview is arguably a good thing as otherwise the candidate may have found working at the company unfulfilling, uninteresting or difficult.