"To me, it goes like this:
IMO there are at least a couple more criteria, those being
(and yes, with the combination of those two items I am still talking about food ...
Some folks, at least, find that buying special "for backpacking" meals is somewhat costly, and of course requires a trip to a sporting goods store or online order. As opposed to just picking up things as part of a normal trip to the grocery store.
By 'easy' I mean little effort in preparation. Perhaps some people truly enjoy making special backpacking meals; when I've done these I've regarded it more as a chore, and tend to eschew such effort now.
And while these could perhaps come under the "nutritious" category, there are other nuances such as limiting sodium intake, issues for those with special dietary desires or requirements (vegan, gluten-free, whatever).
So I would submit that it's a little more complicated. But at the same time I'd agree that it doesn't have to be TOO complicated either!