As to why Cloudflare's 8.37.43.0/24, 8.39.18.0/24, 8.40.140.0/24 and 8.42.172.0/24 networks aren't on that page which purports to be the "definitive source of Cloudflare’s current IP ranges", all I can say is that Cloudflare has a long history of caring much more about the appearance of transparency than about actually being transparent. They make reporting any abuse very difficult, and they probably wouldn't care in the slightest that their customers are doing nefarious things.