While my therapist treats me for bpd, and uses the word "borderline" regularly in our sessions, she still won't write it down as a diagnosis. I was told when I was in high school that I had BPD, but was too young to be officially diagnosed. 14 years later and now they say there's such a stigma attached to it that most people will avoid telling you that you are bpd. So, while I know I have it and my therapist obviously does, I don't get the weird relief and satisfaction of them being upfront and honest with me about my diagnosis 100%

If it bothers you, you can mention it to your therapist. In my opinion, I guess it doesn't matter so much as long as they will treat you for it. I get a little angry sometimes that they won't write it down, but that's just me wanting to be allowed to come to terms with it without people beating around the bush.