The people currently doing the hosting would be the same ones doing the hosting (I’m not talking about every user hosting their own content), they just would choose to host NSFW content or not as they already do by choosing to allow NSFW communities on their instance or not (and would use the necessary tools to cleanup their storage of illegal content as they already do) and users who choose to activate NSFW content in their feed would do it at their own risk (which is pretty much already the case anyway because instances/communities with CSAM don’t get deleted/banned/defederated until someone does it, it’s just your/the other instance’s admin that’s doing it instead of you).
The people currently doing the hosting would be the same ones doing the hosting (I’m not talking about every user hosting their own content), they just would choose to host NSFW content or not as they already do by choosing to allow NSFW communities on their instance or not (and would use the necessary tools to cleanup their storage of illegal content as they already do) and users who choose to activate NSFW content in their feed would do it at their own risk (which is pretty much already the case anyway because instances/communities with CSAM don’t get deleted/banned/defederated until someone does it, it’s just your/the other instance’s admin that’s doing it instead of you).