I just don't think people have the right to be addressed with exactly the precise string of syllables that they demand
But it's THEIR name, not yours. I had a girl at camp named Margaret, not Maggie, just Margaret. It would have really selfish of us to put our feelings before her's and call her Maggie. The exact same thing goes for the girls named Izzy and Maddy. As much as I would have loved to call them Isabelle and Madeline, I called them what they asked to be called.
Whether I like a name or not, I always call someone by the name they are most comfortable with. I would hate to give them the message that I didn't care about their feelings.