The million dollar question????

I substituted today in a high school. At the front of the room behind the teacher's desk the wall was covered with different things. Some pictures, posters, and bumper stickers. Being the curious person I am by nature, I began to read some of the things the teacher had posted for all to see. Amongst the various things there were bumper stickers supporting controversial subjects. As a teacher, I am not allowed to discuss or promote to my students my views on certain subjects. How than is it alright for this teacher to place in plain sight his/her views on certain subjects. When does that teachers rights to freedom of speech over ride my rights to freedom of speech? If that teacher is allowed to promote his/her view freely in the classroom, than I should have the same rights to post and discuss my view points. Unfortunately, this is not the case in our society. This teachers view is a hot topic and is socially acceptable to teach our children while mine is not.