In my opinion if kids leave school without permission they should be given detention or some other form of punishment. If the DODEA schools allow these kids to protest without punishment than what is too stop students from leaving class to protest other hot button topics?:

Parents and students say that administrators initiated an unannounced lockdown drill to stop a planned walkout at Netzaberg Middle School on Thursday, a claim school officials dispute. The incident has raised concerns in the U.S. military community near Grafenwoehr and Vilseck that the school deliberately kept students from speaking out against the removal of material deemed to support diversity, equity and inclusion, as well as the shuttering or reorganization of groups with gender, racial or cultural affiliations. (…….)
Parents and students say that administrators initiated an unannounced lockdown drill to stop a planned walkout at Netzaberg Middle School on Thursday, a claim school officials dispute. The incident has raised concerns in the U.S. military community near Grafenwoehr and Vilseck that the school deliberately kept students from speaking out against the removal of material deemed to support diversity, equity and inclusion, as well as the shuttering or reorganization of groups with gender, racial or cultural affiliations.
You can read more at the link, but if you want to be an activist go do it outside of school hours. However, I am willing to bet it is probably the parents pushing these kids to go and protest during school.