Can you talk about Jesus outside of the classroom, in conversation with friends? Sure. Can Jesus be discussed in Social Studies classes? In the bible as literature classes? In comparative religion classes? Absolutely (although you may like the tenor of some of those conversations, since they'll be analytical, and not simply pro-Jesus). How often is evolution discussed outside of a science class? Does your Art instructor mention it? Does the shop teacher or gym teacher talk about it?
Edit: I'm an instructor, and I'm responsible to deliver a specific curriculum. If I'm teaching a science class, I need to finish what I'm doing, and not allow a single student to side track the class with something that isn't germane to the lessons at hand. If a student wants to discuss matters with me after class, or discuss with fellow students after class, that more than fine with me, it's encouraged. However, freedom of speech doesn't mean you can just say whatever you want WHENEVER you want for as long as you want. There is a time and place for everything. Print media, soapboxes on street corners, and now the internet, are perfect places for the free exchange of ideas.
Can a person enter a Church and begin to denounce religion, and insist that they're not being disruptive under the auspices of freedom of speech? Of course not.