Log: "Dangerous ground" is as close as I can come: subjects the discussion of which--however neutral--is nonetheless risky for fear of offense or misunderstanding. Like, in company one doesn't discuss religion or politics. You don't want to suggest that some sex laws might be overly harsh for fear of being suspected of perversion. In today's conservative atmosphere you mustn't suggest any flaws in the American character else you're branded unpatriotic

Log, don't be disappointed if you can't find the perfect expression. Often there's simply no word for the concept

dalehileman