The kid admitted to not trying to present any particular message. He was just trying to get attention.
http://abcnews.go.com/US/story?id=2953653&page=1&CMP=OTC-RSSFeeds0312
The school charges that Frederick's banner promoted drug use and had an offensive religious message. Frederick said the language, which he had seen on a snowboard, is meaningless.
The courts have held that we have a right to free speech that expresses our views even it that message might be offensive, as long as it isn't unnecessarily offensive.
This brat was just trying to be offensive to gain attention.
He was being intentionally disruptive.
What's next? Are we going to consider streakers that run out on the field at halftime during a football game to be exercising their free speech?
Taking away his sign, which he admits was meaningless to him doesn't infringe upon his right to free speech. Our right to free speech prevents the government from silencing us when we want to express our opinions. It doesn't guarantee that we will be able to express those opinions whenever, wherever, and however we want, but that we will get an opportunity to express them in.
According to him, he didn't have a message or opinion he was trying to express with the sign, so taking it away didn't infringe upon his free speech.
This is an example of an immature kid acting out to get attention, and then the ACLU deciding it is an opportunity to push their own agenda, so the kid gets an even bigger opportunity to get attention.