That's a really difficult question to answer, I think in this case it's ok if there is actually a mental illness or a consequence. I happen to know that my sibling who hates it when anybody chews gum in their vicinity doesn't suffer much from it and doesn't have a poorer quality of life. Them asking me to stop chewing so loudly just makes me feel bad about something I have no control over just as me chewing loudly makes them feel bad because they don't like the sound.