It is certainly true that Arcade Fire’s new album was given an overgenerous rating by Pitchfork, like that of The National. It is also true that it wasn’t given the exact same treatment, regarding rating. However, it’s a different type of album. You have to take into account Pitchfork’s readership. People who get music from commercial radio are not in the same circle.
It’s like comparing a McDonald’s sandwich to one made in a boutique, artisan deli. One is definitely going to be more popular than the other, but it still wont interest a gourmet.