[sinak]

Historically Cloudflare have been quite strong in their support for free speech. For example, they run Project Galileo to protect public-interest sites against DDOS attacks: https://www.cloudflare.com/galileo

I'm guessing in this case it's simply a case of them choosing which battles to fight. They probably don't want to commit to run an open proxy for everyone in China to access banned websites. That would likely get them banned outright in China, which, for a CDN like Cloudflare, would really hurt their core business.