Teachers and Students in Public Schools

My daughter-in-law is an elementary school teacher. Second grade, I think. She comes home with stories like this:

My daughter in law teaches second grade. She is one of the strictest teachers in her elementary school and older, more experienced teachers regularly commend her on the behavior of her students. Yet she is forced to contend with behavior the editorial staff can't ever recall witnessing - even once - the entire time we were in grade school. She has had her students - these are second graders, mind you - choke other students, bite, hit, and throw screaming temper tantrums: all on a daily basis. And there is nothing she can do about it. She cannot eject these disruptive children from her classroom; that would be "depriving them of the opportunity to learn". What about the other students in the classroom? Don't they deserve a chance to learn?