Reading what your friend said to you made me feel really angry and hurt on your behalf. Whoa, that was some harsh stuff.
However, a thought crossed my mind. Could your BFF be harboring romantic feelings for you? Maybe feelings she can't even acknowledge to herself?
'Cause it sounds like her harsh reaction is coming from a place of personal hurt.
Just my theory. I would NOT ask her about it, though. (I may be totally wrong, and it may make things more strained between you).
I think it's great that she talked to you again and that she is sounding more reasonable now.
A short and possibly irrelevant anecdote:
When I was in high school, there was a boy I had a pretty intense crush on. He was in my group of friends, and he dated three of my closest female friends (basically one after the other), inspiring me to wild jealousy combined with the hope that my turn was next. Then he suddenly came out as gay.
I was floored. The school was very LBGT-positive, I had other gay friends, I felt very supportive of gay rights issues--but I had totally not had even the slightest clue that my crush might be gay. He came out to us (his friends) in a way that was very courageous and moving for him, but I was so confused in that moment (my mind frantically questioning everything, what did it mean that he had dated my female friends but not me and then was gay, etc) that I reacted weirdly. I blurted out something stupid, then was embarrassed and tried to turn it into a joke, which made it worse.
He was very cold to me after that, even though I apologized for the foolish comment. He never hung out with me after that, and never really talked to me about it. I kept wanting to confess to him that my reaction had been because I'd had a crush on him, but I never got the courage to tell him. When we graduated, he had a party and invited all our friends but me. I was devastated.
What I'm trying to say is, give your BFF the benefit of the doubt and keep talking to her. She's got her issues, and she's struggling, and she'll miss you if your friendship deteriorates.
Single, straight, female, solo, non-monogamous.