There is a huge topic on this already. Look up topics with “illegal”
To answer your question, you did yourself.
None can know what is stored on their disk.
The ISP cannot be charged for letting data packets flow through there switches/network that contain illegal files/goods/images etc.
The courier company cannot be held responsible for transporting and delivering illegal material
The bus company cannot be held responsible for taking a thief across town, and he even have the loot in his bag
Dropbox is not held responsible for hosting/storing illegal images. AND Dropbox know there is illegal material on the servers somewhere. They just don’t know where and not held responsible because it is unreasonable for them to act as policemen and breach everyone’s privacy in order to find it.
Since SAFE is totally encrypted we don’t know what is being stored on our vaults and are not expected to be able to know. So the same as anything else that provides a generalised service the people operating the service are not responsible for a user of the service breaking the law.
BUT if we were to censor the service then we are held responsible for what we allow through. The same for the ISP, courier or other service provider if they actively censored the items “carried” by the service.
The newpaper or similar is held responsible for what they publish because they are the ones who publish it. All those other service providers are different because they do not “publish” anything. Now SAFEsite operators might be different since they can be considered publishers, BUT SAFE is not responsible for those safesite publishers.
See the difference?