I think you have to give people that benefit of the doubt, and gently stop yourself from redirecting your anger at losing your love one onto someone who has said something daft. It is not easy to know what to say when someone has suffered something so exceptionally painful as the death of a loved one; it's not easy to even process it to yourself when it happens to you.
When my first baby was stillborn, one of the hardest things was actually having to deal with people who just didn't know what to say to me. I really couldn't cope with those pitying looks I got; they drove me mad and just reminded me of how other people saw my situation as deeply tragic when I had actually got to a place where I primarily thought about my baby with deep love and a smile, rather than loss.
I always remember one of my close friends saying to me: "Works, I don't know what to say." And you know what? I though about that and replied: "Don't feel awkward. I wouldn't know what to say to me either."
And the fact is that I wouldn't. What would I say to a woman who had gone through what I did? There is nothing you really can say. And I had an old college mate who said that what had happened "was really fucking shit." And you know what? He was right.
It was really fucking shit.
I also had "These things happen" and "It was meant to be" -- and you know, people were trying to say the right thing. They were trying to make me feel better, or, at least, not make me feel worse.
Maybe, op, that's the way you need to see it. Your friend asked you how you had been since your loss ... see it as her trying. Okay, her effort didn't entirely work, but what does getting offended by what she said afterwards achieve? Apart from you getting stressed about it?