Mannequins in clothing stores are generally incapable of designing or adjusting the clothes they wear. Someone comes in and puts a "kick me" post on the mannequin's face? It's gonna stay there until kicked repeatedly or removed.
People walking around looking at mannequins don't (usually) talk with them (and certainly don't have a full conversation with them, mental faculties notwithstanding)
AI, on the other hand, can (now, or in the future) adjust its output based on conversations with real people. It stands to reason that both sides should be civil -- even if it's only for the benefit of the human side. If we're not required to be civil to AI, it's not likely to be civil back to us. That's going to be very important when we give it buttons to nuke us. Force it to think about humans in a kind way now, or it won't think about humans in a kind way in the future.