The 1st Amendment guarantees freedom of speech and of the press. The idea is that freedom of communication is necessary to a democracy, and this idea was part of English law long before it was written into our Constitution.
But there are also long-accepted exceptions to free speech and free press. Among them are 'hate speech', treason, incitement to violence, and slander and libel. Slander and libel have long been seen to be exempted from free speech laws. The speaker or publisher are responsible for deliberate, malicious lies. The right to publish malicious lies is not covered by freedom of the press.