Telling you “no” is not rude. You likely got tossed into the game hint auto reply category. It would have been better if it told you that CS are not Developers nor do they have access to them. You will not get a Developer to answer you by ticketing CS. They can’t tell you why the Devs did not add an Admiral title.
If you want to make Suggestions you can use the in-game suggestion feature or post on the Discussion forums.
When you ticket for something they can’t do, you are not going to get a reply you wish for.
Here is a great explanation of what GMs can, and more importantly, can’t do.