This is really boobish behavior from Nintendo's side, as far as I can tell. They know they will not get any $$ off of it, just closing the resource. But any company big enough that fighting this is just like fighting windmills.
I've actually been doing some "historical" gaming posts lately, covering noteworthy games released in certain years (just made two about 93 and 2000) and it is perfectly clear that you will not want to bu super old stuff and old systems if you are just a casual gamer, and these ROM sites are just here to keep the legacy going