People (guys usually) also answer like this when they are trying to tell you exactly what you want to hear so that you’ll sleep with them. They feel like if they give any wrong answer early on, they’ve lost their chance. It’s a very manipulative mindset. He was like a deer in the headlights, not knowing if any answer he gave would be the right answer since he doesn’t know her at all yet. So he stalls, hoping she’ll drop it.
Or he might just be an idiot.
Either way, drop them and move on to somebody who will be real with you.