Because if the answer is "it stays accessible" then this technology is fundamentally broken and we need to stop using it or promoting it immediately.
I do get the need to prevent governments snooping on journalists and protesters. But I think there's also a valid need for access to evidence for our justice system to function properly. If we can't convict people without evidence (rightly), and we can't force people to incriminate themselves (rightly), then we must be able to access evidence somehow.
Anyway, the child issue is also a problem vs sanction. Anyone hosting the data in a normal judicial system want will it be ?
In the normal hosting business, content like this is taken down by the hosting provider. For IPFS, a key question has to be "who gets to decide when content should be removed, and how does that happen?". If that person isn't a government because no-one trusts the government, that's fine. But someone needs to be able to make that decision and act on it. Then the usual legal channels can be followed for taking content down if necessary.