We generally do NOT do this.Why not? Because we take the time to answer these questions for free, and answering a question for one person provides information that can then both be there for everyone thereafter, and save us time and effort in answering the same question another time. In threads a user has started where others have participated, deleting them also removes their responses as well.
Moreover, it sets a precedent that isn't so hot: Scarleteen is NOT a funded organization, and deleting a user's posts takes valuable time.
In *some* scenarios (where, for instance a user may have valid personal safety concerns) we'll do it, but as a general rule, that is not something we will do.
What's your particular issue here?