A specious, at best, statement. Using your flawed logic, only a recovered heroin addict, cokehead, pothead, tweaker, alcoholic, nymphomaniac, adulterer, fornicator, thief, etc. can counsel an active heroin addict, cokehead, pothead, tweaker, alcoholic, nymphomaniac, adulterer, fornicator, thief, etc. that their behavior is sinful and they need to amend their lives and expiate their sins.
Obviously you know nothing about the lives of the vast majority of Priests prior to their ordination.
A person seeking counsel does not necessarily commit sin...If a man's wife left him, or a family's child is involved with drugs, etc...
You can attempt to defend all you want, but a single man can not counsel people effectively in these situations...
And yes, a former drug user turned pastor would be a far better counsel that one who had no experience with that type of sin...