Is this an appropriate thing to say to a child?

“Emma” is five and “Amber” is six.

Emma is a shy child and she tends to stand and watch things to get a feel for them before she joins in. She does this almost every time she visits Amber’s house. Amber’s reaction is to pout, throw a tantrum, whine or cry loudly.

After about ten minutes, Emma will loosen up and be tentatively open to playing. Now the tables are turned because Amber is mad at Emma and won’t play with her.

Emma’s mom thinks this is all fine – the kids will work it out.

Amber’s mom tells Emma, “She doesn’t want to play with you now because you hurt her feelings.” This upsets Emma because she thinks she has done something bad when she didn’t mean to.

This is where Emma’s mom has a problem. First, she thinks that Amber should be able to handle someone not playing with her without having a meltdown. No, it isn’t fun, but she thinks Amber’s reaction is out of proportion to what is happening. Second, she does not like that Emma is being blamed for Amber’s feelings or that OR that Amber’s mom, an adult, is telling her that she has done something wrong/mean. Since Emma doesn’t intend to do it but is being told that she is anyway, her mom thinks she will start to feel like a bad person.

I am friends with both of these women and am sort of caught in the middle. It is uncomfortable when I witness this and when they each privately complain about each other to me.