What’s the deal with employers saying they need employees to work certain days/hours, yet getting mad when you tell them that within those days/hours you can work a specific interval within those days/hours?

So, I've been having a few (phone) interviews in the past few days. I want a bartending job at higher-end places. The ads say must be available, nights, overnights, weekends, and holidays. Okay, fine and dandy.

So, I'd tell them (for example): on Thursdays, I'm available only nights, Friday and Saturdays I'm fully available for both nights and overnights, and I'm available on certain holidays depending on which ones you'd think I'd be more needed. So, I'll let holidays more up to their discretion, but I'm open to holidays as a whole.

Somehow, they do not like when I tell them my availability in this overly-detailed manner. They tell me: “no thanks.” I'm like, “what?!” They always ask for what availability do I have… and that's the one I have.