Please differentiate between general NSFW/NSFL and PORN.
It's the difference between LiveLeak and PornHub. For most people, the two are not interchangeable.
They have little to nothing in common in terms of intent and purpose. So those types of content should not be treated as the same. It should be possible to filter/hide them separately.
This would involve splitting the "Is Adult (NSFW)" checkbox on submissions into two. Likewise for the corresponding filter checkbox in the account settings.
Alternatively: Forbid subs dedicated to PORN