My (30M) friend (28F) got mad at me for agreeing with her that her bf was a terrible person. Why do people get upset when you agree with them?

I've been friends with A for 3years. I'm gay so there's never been anything romantic between us. She started dating this guy and he was very controlling, possessive, verbally abusive and also not that attractive. A is beautiful, smart, funny and successful. While they were dating she would constantly tell me all the horrible things he'd say and do. I would just listen and stay very neutral. I've always heard how sensitive people get when you insult their partners.

Anyways, one particular night, when I was driving her home they had a really bad fight, they had been fighting nonstop for a week. She told me she was going to break up with him and she was sure of it. That's when I told her that I thought it was the right call as her light had dimmed and she was way too good for him and I never understood why she dated him.

Next day, I found out she decided to stay with him. Since then, she started being distant with me. We used to have lunch every other week and it stopped and eventually we grew apart. I kept on reaching out and asking if everything was alright and she said it was fine and she was just busy.

That was 3 years ago. I heard from a mutual friend that they are still together and she is still miserable. I guess why do people get mad t their friends for things like this especially since she'd always ask for my opinion on things? I've learned from this and I don't even talk bad about friend's exs. There was one friend of mine whose boyfriend cheated on him constantly. They broke up and our other friends bad mouthed him and I stayed quiet. They got back together and my friend cut contact with the friends who bad mouthed his cheating ex. This is so weird. Why tell your friends if you don't want their honest opinion or support?