Sometimes it's already a compromise between too many people who questioned it, and nobody wants to discuss it any more. Sometimes the questioning is more work than actually doing it. Sometimes you get a reputation of only being in the way.
Make sure the work has been questioned thoroughly, but that doesn't necessarily mean by you.
That's not a leading question. Honestly, both of those goals can be important and effective. But if your goal is to actually effect business change, you'll probably have better luck talking to a product person offline and having the idea come from them.
At the end of the day the work you are doing has an impact on opportunity cost - if you at least internally question the work you are doing, you can potentially lower the opportunity cost and therefore help the business.
However, if you are part of a team of people who consider these things before the work gets to you, I agree it can be counter-productive to question it.