Cloudflare or any other privately owned company doesn't have an obligation to service everyone. They are not violating their free speech, no matter how long you turn it on every side. Kiwi Farms can host their website on any other platform and get any other service they want. No one is forced to service them.

Let's not forget that they have been known to publicise private information of people that ended up with them being swatted. They are a big enable of this behaviour. Not only that, but they have been also involved in three suicides at this point. I don't think any private company wants to associate themselves with such a client.