Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof; or abridging the freedom of speech, or of the press; or the right of the people peaceably to assemble, and to petition the Government for a redress of grievances.

That's the government's entire responsibility regarding 'free-speech'- to not make any laws restricting it. The idea that the government is responsible for protecting your speech by providing a safe space or protecting you from the public consequences of unpopular speech only started when conservatives realized a lot of their speech wasn't popular anymore.