I'm speaking from personal experience when I say that the water temperature doesn't matter.
If a keeper needs to use warm water to loosen the molt on a mantid, because normal room temperature water won't absorb quickly enough, then the keeper needs to re-examine their mantid keeping practice, because their enclosures are obviously not humid enough.
I never said that you said anything about boiling water. Please don't accuse me of putting words into your mouth. What I said was, "So long as you're not spraying boiling hot water at them, any temperature of water should be fine." The "you" used was in a general sense for anyone reading the post. I was not singling you out. The point of that sentence was to emphasize that water temperature does not make a difference.