Nothing about the concept of free speech implies that you have to let perverts show hardcore porn to children. It's a 105-115 IQ libertarian take, much like the idea that it would somehow be bad to arrest and silence every communist in the US or that urban black people should have the same access to guns that non-black people do. No principle worth following obligates you to let yourself be destroyed to follow it.
Nothing about the concept of free speech implies that you have to let perverts show hardcore porn to children. It's a 105-115 IQ libertarian take, much like the idea that it would somehow be bad to arrest and silence every communist in the US or that urban black people should have the same access to guns that non-black people do. No principle worth following obligates you to let yourself be destroyed to follow it.