It's political activism to terminate service over TOS violations?
It was pretty simple really - all they had to do was not lie about Cloudflare endorsing them (per the contract that had extremely standard boilerplate language about such things).
People seem to get really upset when Nazis are held to the same basic contract law standard anyone else would be held to. Just because the politics of promoting hate makes it hard to find vendors, it doesn't mean that vendors need to make a special TOS just to coddle those that do.