Or the one I get all the time: "What makes you think you're smarter than the experts?"

Genuinely, the idea of looking at the evidence and coming to their own conclusion seems alien to them. They just want an answer from someone they perceive as smarter or more capable. Although I suspect that's not quite how it works. Rather, they arrive at their own answer, but for emotional reasons they can't defend; then they look for an "expert" to affirm it, so they can invoke authority instead of having to defend it.