He said something that's a common expression, "taken", which is used for both men and women. It was clearly intended to be a compliment.
You chose an unlikely interpretation that clearly didn't match intent or common usage and decided to get offended about it.
After all your self description, I was wondering "how is she single?"
Right there, now I understand. I'd be out the door. Someone that is looking HARD for ways to be offended is not relationship material.
Think about your need to assign your meanings to other people's words. Maybe talk to a professional. This one thing can sink you.
Good luck!
Relationship material is subjective, and this is a really insensitive way to say you don't think you'd be compatible with them (some might say insensitivity makes someone "not relationship material")
For what it's worth, I'm a man and I understand why that language is off-putting to women. Also more interested in women who are more interested in being the taker than the takee, but I'm weird like that, I think gender scripts have most men seeking women looking for partners to take a more passive role (at least in some regards)
A women for sale is pretty much a whore, so it doesn't seem they read into rather than taking you literally.
But even regardless, the fact that you took his word 'taken' in a literal sense rather than the compliment it was intended as, and here your defending it again rather than reflecting.
If your crossing off guys because they compliment you with common colloquial phrases that you take literally and negatively, well, you will indeed have a short list of suiters.
For some people, “why have you not been taken” may mean nothing more than “I really like you and I can’t believe you are available.”
And if it was a serious question asked early on, I would probably reply with something I don't like about myself, a weakness, if you will. It's not an entirely unreasonable question.