I think the teacher is inexperienced or doesn't know how to handle the child.
I had a similar experience, the teacher in the previous school of my son also complained about him like hitting classmates, not paying attention, not initiative etc. from time to time. I asked in my heart what could I do at home excepting nagging him if you could do nothing at school?
The school he attends now is much much better. My son is still naughty. But the teachers are very experienced and handle him nicely.
Once my son told me he played water and messed up with the toys at school himself, when I started to talk about what is right and wrong, he said, " OK la, teacher has already talked to me, I understand la."
The teachers seldom complain, they only tell me about my son's naughtiness if I ask them myself, and they reassure me that they will help him and teach him how to play with and join the other classmates.
And I can tell you that my son improves everyday, now he tells me that he likes his classmates very much.