"For example, on a job interview, the hiring manager will say something vague like "bad cultural fit" when he really means "This candidate knows more than me. If I hire him, then my own job might be at risk.""

I'm not sure if you're being serious here but is it really hard to believe that you might not be a good fit for a company?

For example, if a company told me they like working weekends and 10 hours a day, and I said I value working smart and think that working too many hours leads to poor quality code, I'm pretty sure both of us would think it's a poor fit.