The problem is not what's important to you when you do an interview. It's not a friendly club, it's the guys who will pay your rent for a while, just act like you pretend to understand this, and ask by side channel, out of sheer strategy.

You CAN refuse once the contract arrives for signature, the interview is a lot also for the company to have argument to sell you to management as a worthy investment.

I admit I never take a guy talking about time off myself, because while I agree it's an important contractual part and something we must give as generously as we can, the fact he asked the first minute of our relationship means it's going to be painful for him and for us, because we're not a paradise company, things can be tough and high pressure (investment bank), people not nice on purpose and sometimes you have to do the right thing rather than the perfect thing, so compliant positive nearly sacrificial profiles will be happily surprised by what's still good while a dude asking "and holidays, 20 or 25 days" the first day will be very sad and burnt out by all the shit.