I would say the problem is the inclusion of the word “public.”

Asking students to create the groundwork for a presentation (letter, website, flash mob) is not unethical, because it’s mostly a way to make students investigate a subject in a less conventional, more practical context. They will understand the ideas with greater depth. It’s a creative means for self-directed education. But forcing them to publicly advocate for that idea is something else entirely. That’s an extension of civics. And if a civics instructor demanded all her students campaign in public for a controversial environmental view that she personally supported, it’s pretty easy to see how this would be a problem. Here again, the issue is not about the subjective accuracy of the concept; it’s about forcing someone without agency to serve as a conduit.

A teacher can compel a student to read a book, but he can’t compel the pupil to philosophically internalize the themes of that book in order to pass the class. He can’t demand that the student write a letter to the local newspaper lauding the book’s author in order to get an A. There are limits to what an academic assignment can require, and one of those limits is the degree to which it spills into the pupil’s nonacademic life. Extending an assignment into the public sphere is an infringement on that student’s right to define his or her public persona. The value of the assignment is not relevant. In this case, the biology teacher has gone one step too far. The educational track is fine, and the motive for the assignment is fine. But the implementation of the assignment outside the classroom should not be part of the grade. You can make a kid write a letter, but you can’t force the kid to mail it. If a student who writes a well-argued letter to a public official still wants to send it, the teacher can say: “That’s great. That’s exactly what I was hoping you would do.” But it should not be part of the grade.