Students only speak in classrooms, apparently.

"What the first sentence expresses is that the central defining feature of Day of Silence—classroom silence—necessitates that teachers who are permitted to accommodate student silence or instructed to accommodate it either exempt students from speaking or create activities around their silence."

Oh, you're absolutely right! Because students can't choose to be silent at lunch time or in hallways or on cell phones or on buses on Day of Silence. Indeed, the only way they can be silent is in the classroom!

"Political protest does not belong in the classroom."

I don't understand how you could make such a claim after considering my above statement.