Voltaire- "I disapprove of what you say, but I will defend to the death your right to say it" if I have got it correct.There's no requirement to respect people's views. There is a requirement to let people express their views.
However, the right to freedom of speech is not absolute and you could argue that some of what CK said was borderline hate speech. Personally, looking at the list the Duke posted, I'd agree with 2 of them, partially agree with 2 more and the rest in my view are nonsense, wrong and in at least one case, downright bizarre. But unless it was hate speech or inciting violence, he had a right to say it in the same way I have a right to say some of it was downright bizarre.