I think that emotional affect is learned and practiced. When you have no accepted template to follow, it takes time to develop one. Would a truly professional mental health worker think it through before asking or before writing about it? How does a psychologist actually know what an inappropriate emotional affect is, especially in a situation new to the person who is being interviewed? I've been in such situations where a teacher actually slapped me for the expression on my face. I'm like seven years old and have no clear idea what is going on, and she isn't going to tell me, and she's beating on me. What was her job again?
Some people simply aren't allowed by others to practice a natural affect. When you don't practice it you don't learn it. Your face takes on an appeasement mode, which others take as ridiculing them or whatever, or an angry mode, or a frightened mode. They don't give you any clues what you are actually "supposed" to do. They hit you. They drive you away. They punish you. They lie about the actual nature of the situation. They contrive to make the situation appear to be different from what it actually is. They do what it takes to induce an "inappropriate" response in their victim. I guess you could say that that is a history of abuse.
What makes them think that their affect or their actions are correct?