In fact, I'd argue that yes men and the under-confident but easy to get along with are the absolute worst kind of employees - They won't tell you that the car is headed off a cliff until it's already three feet off the edge.
Sometimes, forcing someone to answer the very question they have posed is a great way of pointing out any flaws.
The taking of offense here is the bigger enemy to progress than anything else in this exchange, and that didn't come from the interviewee.
I'm all for people being cordial and polite, and many programmers could learn a thing or two about human interaction, but the idea that asking a question in response during an evaluation of capability (on both sides) is an insult is a little bit of a stretch.
Others here seem more interested in giving snarky half-truths.
You don't have to be an argumentative dick to express doubt in something. Nor are you necessarily an underconfident yes man if you dont speak up. Circumstances dictates a lot of behavior.
Even if they're wrong? Well, in that case, good riddance.
In regard to the original situation, I think the interview question in the link is a reasonable one to ask for most places and most positions. The question in reverse is also pretty useful and any candidate genuinely asking it in return (after answering yours) would be a Good Sign. A candidate who doesn't answer, however, and just fires back the question in reverse is showing flags of being an argumentative dick.