Answer

I didn’t understand what you mean by “be lenient.” If such a person comes to ask whether he is allowed to insult someone else, the answer is no. But if he does insult someone, and in our assessment he is acting under compulsion, then of course he is exempt.
Or perhaps you mean: is it permitted to insult him? That is indeed an interesting question. On the face of it, no, because humiliation is prohibited and also creates liability for payment even if the person himself is unaware of it (as with a deaf-mute, an incompetent person, and a minor). See Maimonides, Laws of Injury and Damages 3:4, and elsewhere.