AITA for not saying the kids name in context of something?

Anytime my sisters kid starts acting like a brat, I ask my sister can you please tell your kid to settle down. Instead she just goes "my kid has a name" and my sister will bark at me until I say her kids name. It just seems weird to say the kids name in this context to me. Again it happened kid was being crazy loud, so I had to turn up my headphones. My sisters boyfriend just asks me "is that your headphones that are up that loud" and I said yes because they were screaming and I just wanted some peace and quiet" and I happened to say you and the kid were screaming. But he gets all pissy because I said "the kid" instead of saying the kids name.

Am I the asshole here for not saying the kids name?