A lot of time I ask hard questions like what is the company's revenue model or the company's growth strategy, where do you see the company in 5 years? That can scare a senior developer... then they get angry with me because I have turned the tables and made the person think in a non-binary way.
I have a standard question I ask (in addition to any other curiosity questions): "what is one thing you like about the company/work environment, and what is one thing that you would change if you could?" After a few people it gives a decent picture of what the down sides are.
I'm 90% sure I was rejected by a github recruiter for not having questions. The problem is I know a decent amount about github, and the product the role related to.
And, as you might expect, people do tend to put the answers to the common questions in the job description.
Do you know how team dynamics work day-to-day? What the relationship between the product team and developers is like? Who drives new features? How is work assigned and scheduled? How big are teams? What are teams structured like? Is there frequent movement between teams?
Ask questions that aren't easy to find out without asking current employees, and that don't put employees on the spot. I can do that for hours.
With execs, questions turn more to product roadmaps, marketplace fit, revenues and budgeting, but again, I bet I can come up with interesting and practical questions longer than any slot any interviewer has in their calendar.
It's possible that the recruiter was expecting questions like the above, and saw your reasonable confidence as either over-confidence, incuriosity, or both.
A lot of time I ask hard questions like what is the company's revenue model or the company's growth strategy, where do you see the company in 5 years? That can scare a senior developer... then they get angry with me because I have turned the tables and made the person think in a non-binary way.