How did justice Fortas's concept of "pure speech" extend first amendment free-speech rights i really need help please

Justice Fortas's concept of "pure speech" extend First Amendment free speech rights even though it was speaking, it still was almost a silent protest, which is still considered under the freedom of speech.

Explanation:

This is there paragraph I got it from:

On February 24, 1969, the United States Supreme Court in a 7–2 decision declared the school suspensions unconstitutional. Justice Abe Fortas, who wrote the majority opinion, first established that the students’ action was “akin [similar] to pure speech.” Even though their protest involved no speaking, he argued, it deserved “protection under the First Amendment.” In the key passage of the opinion, Justice Fortas wrote:

"It can hardly be argued that either students or teachers shed their constitutional rights to freedom of speech or expression at the schoolhouse gate."

-United States Supreme Court Justice Abe Fortas

- "it was a failure that was an embarrassment for the kennedy administration."

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