You are, of course, correct. And in the absence of any context, I'd say those questions must be answered. Note that the time required to get them answered (requirements gathering) should also be estimated.
However, in most cases, there is a surrounding context to that set of "requirements" I gave, so you'd probably be able to answer accurately.
The overall point is that you still have some idea of (a) how long it will take and (b) what level of confidence you have in the estimate.
I hate to go back and forth, but I spent 6 years doing freelance work, and I hate to see people repeating my mistakes. They can be costly. I would "probably" be able to answer accurately, but we're definitely talking probabilities here.
I learned that estimating was really a negotiation of risk. When I put an estimate down on paper, I'm saying to a customer, "I accept responsibility to deliver the product for this price." I'm taking on the risk if I don't, so I pumped the prices up. Also keep in mind that "the product" is what's in the customer's mind, not yours.
At some point I decided that I needed to have the "risk negotiation" conversation with all new clients in very candid language. Once a client is aware that they're paying for you to take the risk, they're usually willing to buy some of it back. Customers who were willing to buy back some risk always turned out to be better to work with than customers who wanted to offload all the risk to us. It turned out to be a marker by which I would steer the course of client development.
However, in most cases, there is a surrounding context to that set of "requirements" I gave, so you'd probably be able to answer accurately.
The overall point is that you still have some idea of (a) how long it will take and (b) what level of confidence you have in the estimate.