If the question of whether or not there would be a concrete benefit to marketing NFS in EA's stead is irrelevant and pointless, how could Nintendo be in the wrong for not doing it?
Trying to sway opinions often relies on tactics that may not present clear, quantifiable results. Its not like "Ok, if we spend 2 million dollars for this one title's advertising, then we will get 7.5 more support points from EA". That's not how these kind of businesses work, even though that is exactly what Nintendo need, EA's support and that's only going to happen if they have a good relationship.
Nintendo is having a huge problem with third party support in general. Showing support for a title based solely just on quality, is going to have a positive effect on third party relations. It is what is called a "gesture" of goodwill, which has been lacking. Nintendo is notorious for poor third party relations. Just look at what went down with EA. Now they have nothing to show from the largest third party. My opinion is that supporting NFS more aggressively, based on the fact that effort was put into the port to make it clearly superior to the legacy hardware it arrived on previously, effort no other developer was seeming to put into their titles save Ubisoft, would have gone a long way to start changing opinions. Ignoring a title that clearly had a lot of hard work put into it, above and beyond what others were doing, even if there were frosty relations with EA, was not wise.
How unwise is not quantifiable. Again, its not like we can point to an example where MS and Sony had to do something similar, and its not like we can make a guess of how many positive opinion points they get towards a publisher as such a thing doesn't exist. But opinions do exist, quantifiable or not.
Forming this opinion is not some huge leap in logic. Not everything in business boils down to a formula or precedent, especially when Nintendo is in a position no other major hardware provider has been in, perhaps with the exception of Sega and the Dreamcast if you still considered them major after the Saturn. Even if we cannot know what actually could have resulted from aggressive support, does not mean it was not a mistake to do so. These gestures are not meaningless or forgotten. Perhaps the benefit may not even materialize until their next platform. But Nintendo has to become more aggressive. There is a reason why EA has not abandoned MS or Sony but has shunned Nintendo.
I do not fault someone for disagreeing with the opinion, but you can't just say "well that opinion needs solid proof". This is the kind of opinion where solid proof is just not going to exist and is not necessary.
So when you ask "What was the last 5 month late port from Microsoft or Nintendo that Sony advertised? Honest question, while we're criticizing Nintendo for not advertising an EA (one of the biggest publishers in the industry) game when EA itself wouldn't advertise it."
Its an empty question. MS and Sony don't really advertise games that had little support from their publisher as they usually are getting all their biggest games anyway. MS and Sony do not have any issues with EA or any other major publisher. There is no need to make a big deal out of a port as the publisher is perfectly happy and willing to support anything they put out on those systems. So when Madden is ported over, often with less features, but perhaps shinier graphics onto Xbox One or PS4, there is no worry about EA's support.
But when Nintendo is a unique situation where one of the biggest publishers in the world is pulling the plug on support and you do not wish to support the one title a developer put time and effort into, one of the only ports to actually differentiate itself in quality from the other cross gen ports you are getting. Well In my opinion, that's a mistake.