This is insanely dumb. Cloudflare is providing free hosting services, not materially supporting the attacker. You can argue that cloudflare needs to be better, or adopt different values towards, taking down sites they host, but this organization could absolutely just serve elsewhere (or just advertise their services over telegram or the like).

Maybe there is a point to be made about monopoly power in hosting and ddos protection. I don't really see how this blog post, or labelling it blackmail, help make that point.

It's not dumb. There's a conflict of interest.