The First Amendment is not absolute, it has limits. As important as those limits are, it is even more important that the First Amendment, and its limits, apply to everyone equally.
Whether based on the spirit, legal or societal commitment to the First Amendment, it is easy to start carving out exceptions to protect segments of society in unusual situations. Easy is rarely right or good. We choose easy because new definitions and demarcations can be very difficult. Even understanding that free speech is not absolute is hard. Even harder when we start talking about exactly where those limits are.
The fundamental absolute about the First Amendment is that it was intended to be as dynamic and changeable as the Constitution itself. That's why the founding fathers built-in a the capability to make amendments. The First Amendment and the Constitution were created by mortal men, but men smart enough to know that change is the only constant in the universe. Change is inevitable, necessary and rarely easy. A static and rigid U.S. Constitution would be no better than the Russian Constitution. When have you heard anyone discuss the Russian Constitution?