It's disrespectful to hear someone correct the way you pronounce their name and then refuse to adjust your pronunciation. Unique names or nicknames give people individuality and especially when kids are growing up, hearing someone butcher their name over and over again can be disheartening and offensive. Names are a huge part of our identity, and even if you think you know the "right" or "proper" way to pronounce "Brian," if someone tells you their name is "Bree-an," that's their name, not yours. If celebrities can name their children Apple Klondike Antarctica Soldier Kinder III and everyone accepts it, a teacher can learn how to pronounce their own student's names.
So, when a dad decided to consult the internet's moral compass of Reddit's "Am I the As*hole?" about his daughter's teacher's refusal to pronounce his daughter's name properly, people were ready to offer advice.