My first thought was "But I like how your voice sounds. It sounds friendly and kind!" But it's YOUR voice. I'M not the one who needs to like it. And while it's good to be accepting of people just the way they are, it's equally important to accept people wanting to change something about themselves.
So if anyone else had a similar thought, it's okay to have that reflexive thought, but you have to remind yourself that it's not about you. They have to live with it. And if it doesn't work for them, it doesn't matter whether you like it or not.
And if you care about them, you should care about what's best for them, and that they're comfortable with who they are and their self-expression.