If one wants to add insult to injury before launching a rebuke of someone's position, he usually will preface his remarks with "with all due respect". With all due respect, there is no respect intended, only an attempt to belittle another's point of view by hitting him below the belt. On the other hand, perhaps the person being criticized does command respect. All in all, getting right to the point would hit the nail on the head no matter the circumstances! If that doesn't cut it, maybe its time to zip it.