Hi, personally I feel you're both right. Each set of parents has the right to know how their child's day went both positively & not so and yes at 2 years old communication is still very much in its infancy and understanding right & wrong/moral development is more likely to be seen at around 4 yrs old.
This quote is from
page 330 of the new workbased learners handbook '
Morality is a set of beliefs about what is wrong and right. These in turn determine our behaviours. Young children tend not to have a belief system of their own. Instead, between birth and 4 years it is thought that they work out what is right and wrong according to the reactions of adults around them in a very primitive way'.
One way that A. Bandura's social learning and role model theories might arguably play out in your situation is that a parent punishes the child for not doing the right thing eg. electing not to hit, so a child comes to learn that it's acceptable to punish/hurt another emotionally or physically for not doing what they feel is the right thing, that could be a peer not handing over a toy when a child asks for it.
Do you have any story books or ways of working that you can share with your horrified parent so that their reaction to this type of news now & for the future is reasoned and that they know you're always there to talk things through with them?
xx