Parents who respond

[Trace of Angels]

I have a DCG who has been in my care for a while. She has always been my "passionate one" Whenever she doesn't get her way it is a full on screaming tantrum. I ignore it and then try to give her the words to express how she is feeling and explain to her how to get what she wants (asking nicely, waiting her turn etc etc)
I have noticed that her parents respond to the scream. This morning they bring their child with an item from home for sharing. It doesn't go well from the minute she walks in the door. She is screaming mine. When she puts the toy down and someone else picks it up she screams and doesn't stop. The mom says "you need to share" When the other little one drops it as she is so scared from all the screaming mom quickly gives it right back to her little one.
She offered to take the item home, but I pointed out right away that that was why she doesn't do well with sharing. I pointed out that mom didn't make her and gave it right back to her own daughter as she was responding to the screaming.
I feel bad but should I just mind my own P's and Q's
Do you find that children who are parented one way at home can respond to different parenting at daycare?
WWYD with parents who respond to the scream would you say anything if it was affecting your day to day?