Do you believe your ISP should be allowed to drop you if you say something they don't like? What about your phone company? We, as a society, already forcing companies to support content they don't endorse.
Cloudflare is doing neither here. This is closer to Subway banning you than your phone company; it's highly optional to do business with CF.
What about an airline terminal?
We, as a society, are already denying individuals and organizations the right to disseminate information while using our private property when it doesn't align with our goals and beliefs.
The disagreement here seems to over whether Cloudflare is more like a restaurant, or more like a utility company. Given the ubiquity of DDOS attacks online, (and the fact that KF seemingly can't stay online without DDOS mitigation), I think there's a good argument to be made that DDOS mitigation might be more like a utility.