The candidate didn't do the equivalent of "get lost."

I have been flushed from an interview process halfway through. (Apparently I failed the personality test for Capital One. Fair enough.) They had a car take me back to the airport. I didn't mind. The guy I was riding with (who was also flushed) was really pissed about it, though.

A company really should solicit feedback from the candidate during the process. The candidate can say "I don't think this company is going to be a good fit," and then the company can decide if there's anything more worth talking about. Maybe there is, maybe there isn't.