Interesting possibilities.
Maybe students see school as an example of government control. In schools, students lose many rights that aren't politically correct. They may not be allowed to speak out against, for instance, (whatever the name is for) homosexuality-acceptance week, while homosexual students are allowed to speak out against regular students all the time and can prevent a "straight"-acceptance week.
Perhaps the students are simply recognizing the way our government works, or perhaps the students realize it might not always be a good idea to let our enemies say/publish anything they like here. Despite the guarantees of the 1st amendment, government may still infrige upon these rights (such as freedom of speech) during war.
The rebellion syndrome.