Yeah, and point two is just shifting the problem of definition to "patently offensive".

I think the last point (while absolutely not what I would use to construct such a definition) would be the basic defense for most manga that aren't smut, since even if it has smutty elements (or just engages with the concept of sexuality), it is usually a minority of what is going on in the work, so you just need to defend the rest of the work as literary and legally it's done. I guess this is pretty precision-targeted at dedicated porn distribution and that sort of thing rather than really resolving the question of "what kind of sexuality is okay to depict?"