Speaking as a current student, teachers with a more neutral stance open up more discussions. Besides, politics became prominent during the presidential elections in 7th grade (when I was 12), and parents influence children on almost everything. We become exposed to different opinions and ideas since conception and politically in our early teens. When everyone has an opinion and claims to know what’s best for us, having someone who won’t judge our thoughts allows for a greater and more open exchange of ideas. It also allows students to critically think without an expectation to choose a certain path or answer.
The second argument I would add to your position is this: if a portion of my grades are up to an evangelical teacher, do I really want to take a stance against him/her? Is there suddenly a “right” answer?
Thanks for posting!