Frankly, to me this has nothing to do with the context in which it was used. If someone feels comfortable to say bigoted slurs casually while they are trying to make a point, it doesn't make a slur any less bigoted. What it tells me is that the person is completely unaware of the fact that the word they used is offensive, which means that in their lexicon the word is normalized. To me it's even worse than when someone uses it intentionally, fully knowing that it's offensive, because in the latter case the bigoted attitude is consciously chosen and, therefore, can be easily seen and confronted. The unconscious bigotry is harder to see for what it is and to fight because the person themselves is unaware of what they are doing.

When the therapist is on such a low level of conscious awareness of how their words may sound to and be received by others (as you noticed correctly, it didn't even occur to her that you may be gay) and when they are so out of touch with where the society stands on social issues these days, I don't see how they can offer meaningful insight on anything.

By the way, I am not really a "social justice warrior" and a defender of the PC culture. I think, oftentimes, it goes too far to the point that things get twisted and issues are made out of nothing. But this is not that kind of a case. This is just pure ignorance on display.

Not to mention that, as others noticed, the therapist did breach confidentiality. She doesn't have to tell you the name of the client to do that. Just telling you about the other client's specific issues is enough to consider it a breach of confidentiality. The fact that it was done with the intention to help you doesn't justify it and doesn't change the fact that it's a breach, which is not only unethical but also illegal. There were better ways for her to illustrate the point. She could've just said that she had experience working with people with the issues similar to yours and some of the things that helped were A,B, C...fill in the blank. There are many ways to illustrate the point with examples without breaching other clients' confidentiality. Also, if she used another client's case to help you, she, certainly, wouldn't hesitate to use your case to help someone else. And, who knows what kind of adjectives she'd use to describe you to her other clients and, may be, not only clients..Ask yourself if you are comfortable with that.

Not telling you what to do. Just saying that to me the therapy would end right there without getting started.