Okay well he's 6 and in Kindergarten.
Kids this age are not mature.
However, in a school setting, there are rules and kids need to learn how.... to behave in, school.
Also in school, there are other kids. And the vibes and dynamics of the kids, PLUS in conjunction with kids who are tired/hungry/fussy and other distractions etc., it just feeds off on other kids.
However, again, kids need to learn how to behave.
AND certain kids, DO know how, but still misbehave. Knowingly.
I work at an elementary school.
All schools, have rules.
And in a classroom full of Kindergarteners... well, even 1 kid being errant... can and does, affect the rest... of... the .... class.
So that is also why... Teachers, have to, do something about it.
Other kids also go home and tell their parents, what kid makes trouble etc. and how it is irritating etc., then the parent goes and asks the Teacher about it and then, if a Teacher is not managing her classroom, in a manner that 'pleases' the parent... the parent may get irked and complain... about the Teacher, and/or with a classroom that is disruptive.
So, it is a domino, effect.
And it happens, every day.
Make sure your son is well rested and gets enough sleep.
Make sure he is... eating lunch.
MANY kids, do not eat lunch. Why? Because, they are TOO busy.... fooling around, at lunch time in the cafeteria. And then, it bothers other kids who then cannot eat... either. And it becomes just one pile of trouble. For the other students as well.
I know. I see it everyday, per kids who fuss around and lunch and bother the other kids.
Punishing him at home, is not necessarily going to solve it.
The school, per whatever their approach is, has to manage him, as well.
Because, it is a classroom and school disruption.
I see even 5th graders acting this way.
And let me tell you, by this age, there is no excuse for behavior like that.
And other students, complain... about those kids too, who make trouble.
Schools have rules.
Just like anything else in life, and even once we become adults, in an office.
Sure your son is young.
But, at some point, hopefully, he will even out.