What is the group libel?How can you use the concept of group libel to build the argument in favour of regulating hate speech?

Week Ten – The Harm of Hate Speech
Waldron argues that there are two important things that are threatened when hate speech is unregulated. What are these?
Waldron briefly mentions a few of the arguments made by opponents of free speech. What are these?
What is the difference between hate speech and hate crimes?
What is the group libel?How can you use the concept of group libel to build the argument in favour of regulating hate speech?
How should we address speech that harms dignity without inciting hatred? Is there a slippery slope?