It's not a "brochure", it's how they meet their customers and take payment from them for their attacks. It's how they make it so anyone in the world can launch a 100Gbps+ attack in 5 minutes for $20.
If you get DDoS attacked, you panic and look for expensive DDoS mitigation, or you go out of business. Legally, enforcement for the specific attacker is almost impossible. Cloudflare both knows this and benefits from protecting it. They realize that customer connection is critical to the system functioning and yet continue to defend it.
