Law is not cut and dry. It is all arguable.
The main issue with law is that laws vary widely around the world. Country A may state something is legal and country B not. It is not possible to know every law so the legal question is not determinable.
Also there are issues such as Wikileaks. Would IPFS allow wikileaks to post material? Wikileaks has given rise to considerable comment and the US Government has pursued various people connected with Wikileaks. So would IPFS simply prohibit wikileaks?
Already many US sites are banned around the world and for example youtube is banned (and blocked) in UK schools as being unsuitable. Google is also banned in UK schools as being unsuitable. So if Google tried to post material, would IPFS allow that?