Calling Data a "robot" demeans everthing Data is. Seven should know better as she is not some idiotic ensign who does not know better. And she keeps being bitter about Shaw deadnaming her. Why would she choose to do something just as horrible to Data? She is calling him in essence "stupid" and "Less than he is" by using the term "Robot", and by saying "Your Robot" suggests Data is a slave to the TNG crew. It's horrible.
Pulaski only had to be corrected once. I see no problem with Seven making a similar error. She has no shared background with Data. How would she know better? She won't be doing it again, because she will relate to how he felt when she said it. One error is permissible. Shaw deliberately made his error over and over.