I am sorry to hear that it is part of your life as well. Bullying someone for that is especially harsh. I am very sorry that happened to you.
I think that I reacted this way because I saw other memes and stuff making fun of anorexia or treating it very lightly. That hurts when you are still in mourning. I now understand that this is not what you meant to do and I apologize if I responded too angry.
I think another reason for it is that the picture actually triggered the memory of my sister when she was very ill in the weeks before she died. It is very difficult to explain the mixture of love and horror I felt when seeing her during that time. But your work made me think of it. This is okay, it is part of her and my life and I need to accept that. But I did not expect it and I think that I responded more emotional because of it.
I think it is in a way very good that you are able to express something that is so complex in a way that I responded to it immediately. I think it shows you have talent. I now think it was not a random trigger, but actually recognition of a shared experience.