J.G.
I recently taught elementary in Texas in two different cities - the children's behavior in one city was very different than the other city. Biggest difference between the two was the ethnicities and the parent's involvement. Both places had low socio-economic students. Both schools expected the highest level of respect from their students.
I'm so sorry to hear that you are dealing with this. I don't think it is all public schools. I think it has to do with the values that parents teach at home. The very misbehaved children in one place I taught had parents who did not even respect the teacher. Once, a student told his teacher "My mamma said I ain't got to listen to you cause you white." How can you teach someone like that??
Often, the great teachers can gain respect of their classroom, but it is not easy when children come to school with no value in their education. And to find a teacher that can do that with their whole classroom is hard enough. There are few and far between.