Personally I think people should generally be polite and respectful towards the models. Not because they have feelings, but because cruelty degrades those who practice it.
It's the same reason why I tend to be good to RPG NPCs, except if I'm purposefully role playing an evil character. But then it's not me doing the conversation, it's the character. When I'm identifying with the character, I'll always pick the polite option and feel bad if I mistreat an NPC, even if there's obviously no consciousness involved.