To give racist equivalents, it's as if in the USA, imagine you came into the room and there was a latino man there "Are you the new cleaner?"; or in UK, imagine one was introduced to a new eastern european member of staff, "Are you the new cleaner?".
In this case, there are other cues that a person can use.
e.g. if the person's wearing a cleaners' uniform, it's not racist to ask them that. If they are wearing a suit, it's at a minimum socially clueless, and at worst bigoted to ask them that.