They do, and CloudFlare has historically been part of the reason why they have such high DDoS risks. There's a bunch of "booter" sites out there which effective

They do, and CloudFlare has historically been part of the reason why they have such high DDoS risks. There's a bunch of "booter" sites out there which effectively sell botnet-as-a-service DDoS attacks to gamers, and those sites have relied on CloudFlare to stay online. Without that protection their competitors would DDoS their websites offline most of the time. Also, most reputable hosting and CDN services don't allow booters because they're both highly illegal and disruptive to the entire internet. CloudFlare, on the other hand, openly permits them.