There are plenty of legal ways Christian students can promote their views in public schools. They can start a club. They can gather around the flagpole. They can host voluntary Bible studies. They can talk to their friends about Jesus during lunch (at least until they run out of friends to annoy).
Basically, it’s all good as long as teachers and administrators don’t get involved in any substantive way in order to avoid coercion.
But back in May, Robert Basevitz filed a lawsuit against the Fremont RE-2 School District in Colorado, documenting all sorts of instances in which District officials crossed the line and treated the local high school as an extension of a local church.