If it had been me, I would walk away and read it again. If I still found it hurtful I too would reply with "I'm sure this isn't what you meant, but..." I need closure, otherwise it would bother me forever. Since it was a friend I'd like to think it was just a miscommunication.

Had I been the author, I would like my friend to ask me what was going on. Sometimes I'm distracted or in a hurry and perhaps the way I verbalize something in that state comes out differently than I intended it.