Macy's interview questions

I was interviewed by one of the department managers instead of the HR manager. I had been called for the interview after submitting an online application. In the application, I indicated I was unavailable to work on Sunday. My interview consisted of being asked if I could work on Sunday, to which I replied no. I was told if I didn't have completely unobstructed availability, I could not be hired. I asked if it was possible to work some, but not all Sundays as I could try to work around a portion of my Sunday commitments. I was told absolutely not. End of interview. If that was the criteria, why was I called for the interview in the first place?