I'm not going to say that the review is inherently unfair; taken on its own I don't see enough of a bias to be worth comment-- especially given that the assessment of the X13 is generally positive.
But I've noticed this trend regarding reviews for ThinkPads wherein they are compared to competing products which are not of the same product class (or not of the same generation). The impression left with the reader/viewer is that the choice of a Thinkpad is always a sacrifice one makes for a robust build and/or excellent keyboard. But that impression doesn't really hold up when like is compared with like.
Imagine reading a review of a Dell Inspiron which drew comparisons with it and a MacBook Pro. Perhaps there is such a review, but I'd expect that most reviews would probably use business-class HP, Acer, or Asus models for comparison purposes. But when it comes to ThinkPads -- from "Premium Ultrabook" X1-Series all the way down the range to entry-level E-Series -- all ThinkPads get compared with the top-of-the-line machines from the competition.