When persuading, Germans feel obligated to present the Gesamtbild, the full picture, all of the facts, the pretty as well as the less pretty, what works, what does not.
This is a Bringschuld, literally bring or deliver obligation. The German presenter does not wait until critical questions from the audience pull out or expose the weaknesses of an argument. In Germany it is a sign of competence, professionalism, honesty and integrity to reveal openly the weaknesses of what is being presented.
An attempt to conceal the weaknesses of an argument, offering, concept or solution leaves a German listener with only two possible explanations. The presenter either is not aware of the weaknesses, and is therefore not fully competent, or the presenter is indeed aware but trying to conceal the weaknesses, and therefore dishonest.
Either way the presenter will not persuade the German listener. And worse, the presenter‘s credibility has been damaged severely.