As mentioned, you definitely shouldn't have to "argue" with the front desk person to get that upgrade. (Assuming that the room in question wasn't also a suite room.)

During the "discussions", did you speak with a manager? I ask as it is possible that the problem was a lack of training for the front desk person you spoke with rather than the hotel attempted to go with their own rules. If you did not, I would suggest you contact the hotel management and ask them what they consider the policy to be. If they agree that the front desk person was incorrect, then you can let them know who that person was and they can work on that person's training.