What's their basis for that? I'd have thought at the very best it'd be about the same speed as a 13" (assuming you're not doing anything that uses much RAM; the 4GB would really cripple it there). I'll be interested to see what CPU it has, exactly, but I'd be surprised if it has the HD540/640 graphics.
EDIT: Specs here: https://i.imgur.com/Kc1fQ52.png
The expensive ones use an Iris 640, so are the Kaby Lake incarnation of the chips used in the non-TB 13" Macbook Pros (the touchbar ones use the higher wattage chips with Iris 545). The cheaper ones use HD 620. So, the more expensive models might be comparable to the non-touchbar Macbook Pro; it's unlikely that the cheaper ones will be.