Hays interview questions

There were four rounds. First was a mix of role-play and behavioral questions. Second was very short and more behavioral questions. Third was the assessment center. And finally a talk with the director. Overall, everyone was nice and I had a good talk with the manager who led the assessment center. However, the final interview left me puzzled because the director only asked a few questions but then determined they had a good idea of who I was. Then I ended up not getting the job. Their reasoning was because I did not have a sales background. My question is: Why string someone along through four rounds to only decline them for something you would have known just by looking at my resume??????? In the end, waste of time. Don't apply if you have no sales background.