The point is these things happens. In all grades, in all ages.
The thing is: I teach my kids that not all kids or Adults, are fair/nice/correct/gracious/thoughtful. And it has NOTHING to do with you... because if you observe the child, they do this to other kids too. BUT that THEY have a choice and can make friends with other kids, too. Don't get wrapped up in another kid's drama or making trouble. But, if something is wrong/mean... then tell the Teacher.
I teach my kids, that there is a difference, between people... doing things like that to everyone or to just them. Singly. Then, they can always tell me. And if it is a problem with only my child, then I speak to the teacher and they can also speak up to the child and to the Teacher.
But things like this happens all the time. And sometimes there is no reason. Some people/kids, are just not as fair or nice. But don't take it personally.
AND that they CHOOSE, their friends. And to "DISCERN" people and their intentions and actions.
My kids are 5 and 9. And they have become good at discerning, because I have always spoken to them about stuff like this, about people and scenarios. So that, they can think on their own and not get swept up into... other kids making trouble or creating drama.
And if something inappropriate is happening, they know... to speak up and/or tell me and the teacher. They also know how to stand up to other kids and speak up.
Human nature. These things will happen.
Some kids, just really make drama. And usually it is the kid's own, issues.
Of which, the Teacher is usually VERY well aware, of that fact. And how it can affect, the other kids.
If it is negatively affecting other kids or your kid, then tell the Teacher.
But in a classroom full of kids, there will always be, those that create drama and/or are not nice. Not all kids, are nice. I teach my kids that as well. So they need to use, their inner radar and discern.
This is only among 4 year olds.
Just wait, until your child goes onto other grade levels.
At my kids' school, the Teacher will always talk to the class as a whole, about conduct. And will, privately with the parent, talk to the parent if their child is instigating negative behavior or doing bad behavior to others.
Even adults, can be this way.