I know what you mean, but like you said that's most likely due to the fact we rarely encounter other Chee. Most of the few we have met seem just as human to me though. They've had more than enough practice at it.
Aside from being made of metal, the Chee are barely any different from any other living being. They are sentient androids, meaning that they can think and feel for themselves, make decisions, be affected by consequences, etc.