Cloudflare is in the business of protecting websites from DDOS attacks (and various other things). They should of course try to estimate the cost of protecting

Cloudflare is in the business of protecting websites from DDOS attacks (and various other things). They should of course try to estimate the cost of protecting a given client, and forward that cost onto them. However, if that client is willing to pay, their business centers around protecting them. I highly doubt daily stormer is their worst client in terms of DDOS protection or any other service.