According to the video:
American model of free speech, which largely rejects hate speech laws, is essential because governments and institutions should not have the power to decide which ideas are acceptable. They argue that restricting speech does more than silence offensive opinions, it shapes what people are able to think, discourages open debate, and makes society less resilient by suppressing controversial or unpopular viewpoints. While acknowledging that hate speech laws are intended to protect vulnerable groups, the speaker contends that in practice such laws mainly protect the authority and narratives of those in power. They conclude that true intellectual freedom requires allowing even offensive or unpopular ideas to be expressed so they can be challenged rather than censored.
Total freedom of speech is the most obvious example of the paradox of tolerance.
Fascists rise to power. They silence their critics, corrupt the judiciary and other independent organs of state power.
They are eventually destroyed by liberal forces.
Liberalism then creates a system of free speech, giving all voices equal credence and is tolerant of hate speech.
Fascists use that tolerance to further spread their messaging, eventually leading to the downfall of liberal democracy and a rise of fascist totalitarianism/populist etc etc.