boyfriends sister screams at her baby 😦

Okay so last night I was at my boyfriends house watching a movie. We went downstairs which we never do, but the tv is bigger for a movie so we decided to. His younger sister lives down stairs she's 19 I believe almost 20 and she just had her first baby back in January. So anyways, I was watching the movie he went up stairs to get our food and I hear his sister screaming at this baby. She said "shut the fuck up crying you get on my fucking nerves shut the fuck up" it made me feel really weird and now I don't even know what to think. I could just never imagine screaming at a baby like that 😔😤😷🤔