Violent behavior is never acceptable. What we do know is that children do have a broad range of aggressive or violent behaviors that we do need to recognize. We can see something as common place as pushing and hitting in the playground and carry it forward to children who are significantly getting into trouble and fights so aggressive that legal action is involved. What we do need to understand is that there needs to be an intervention if a child is consistently engaging in some type of violent act. Secondly, we need to understand the etiology of where this aggression is coming from.
Children learn this type of behavior from their environment, so whether it's at home or their community, it's something that does need to be addressed. Violent behavior can stem from many different clinical disorders, from something as more common as ADHD to various psychotic behaviors. If you suspect that your child's violence and aggression is getting completely out of hand you, absolutely must contact your pediatrician, or someone at the school, or your community to get help.