It’s a matter of going after those with deep pockets. From Wired:

Cloudflare was sued in November 2018 by Mon Cheri Bridals and Maggie Sottero Designs, two wedding dress manufacturers and sellers that alleged Cloudflare was guilty of contributory copyright infringement because it didn’t terminate services for websites that infringed on the dressmakers’ copyrighted designs….

[Judge] Chhabria noted that the dressmakers have been harmed “by the proliferation of counterfeit retailers that sell knock-off dresses using the plaintiffs’ copyrighted images” and that they have “gone after the infringers in a range of actions, but to no avail — every time a website is successfully shut down, a new one takes its place.” Chhabria continued, “In an effort to more effectively stamp out infringement, the plaintiffs now go after a service common to many of the infringers: Cloudflare. The plaintiffs claim that Cloudflare contributes to the underlying copyright infringement by providing infringers with caching, content delivery, and security services. Because a reasonable jury could not — at least on this record — conclude that Cloudflare materially contributes to the underlying copyright infringement, the plaintiffs’ motion for summary judgment is denied and Cloudflare’s motion for summary judgment is granted.”

I was an expert witness for Cloudflare in this case, basically explaining to the court how the service works.