It's unreasonable to expect cloudflare etc to be able to proactively identify legal vs illegal streams. The companies who own the copyrights can't even get that right much less a third party that has no idea if a stream is licensed.
Who said proactively?
Cloudflare can assign IPs based off customer reputation. High risk customers get high risk IPs. This way legitimate businesses stay on IPs that don't get blacklisted and sketchier businesses go on high risk IPs before they potentially get banned.
Why though? Why is it unreasonable to expect a company to have some level of responsibility for serving clients that are using their platform for illegal activity?
It the same thing with social media and moderation. We don't have to let them off the hook just because doing the right thing would make them unprofitable.