This is fair. I think because comic books are so drenched in continuity, though often with far more errors and logic gaps than these films, fans expect some semblance of that. And I do think it textures a long running series like Star Wars quite well. Yet even there, there are continuity gaps that nobody cares about when The Force Awakens is entertaining.
So yep, I think people latch onto this because it is a noticeable issue with this particular franchise while Marvel Studios does not have it, so they keep beating the drum. I just wish they were as demanding of Marvel to come up with a villain half as good as Magneto or a third act as exhilarating as Days of Future Past, but here we are.