Same-sex classrooms in South Carolina

We have blogged about same-sex classrooms in public schools previously and this article out of Greenville, SC does not appear to say anything new about the situation. It is a quite balanced piece that uses narratives from same-sex classroom teachers and parents as well as research and testimony from educational researchers. Again, it is a lot of the same things we have heard: some students do well in this environment, some test scores are up, most of the same-sex classrooms reify gender stereotypes, the research on the success of these spaces is suspect.
What prompted this posting was the picture attached to the article. It shows boys in a "dukes up" pose. The teacher who appears to be a woman is in a similar pose but we only see her arms.
The article contains numerous descriptions about classroom decorations (the boys have sports paraphernalia and the girls have gingham and flower pots) and behaviors (the boys get to stand on chairs and recite spelling lists and jump around between lessons). All these things are worrisome in themselves. But why are schools teaching boys to box? And why was this activity missing from the text of the article?
Proponents of sex-segregated classrooms counter naysayers who worry about the lack of mixed gender socialization saying that girls and boys can socialize during recess and lunch and before and after school. But what kind of socialization occurs when boys are raising their fists and girls are planting flowers?