Nicknaming your child an ugly name?

My inlaws are driving me insane!!! They call my son who's name is David doody as a nickname and it pisses me the hell off!!! I'm due with my second and they want me to honor their family and name after them but they killed all possibility of that by continuing to call my child doody to piss me off. They are aware that I hate it and im about to kill them. I told my husband im not going to see his stupid family again till they swear to stop doing it. It's ridiculous. They are Europeans and the nickname for David in Yiddish can sometimes be dudu or doody which I hate. I'm not European and to me doody =💩 how the hell do i get them to stfu and stop doing this??? I'm so pissed and thought about letting them know how they killed all chances of me naming after their family.