The whole point of Digital Foundry is to analyze in full detail the performance of the software relative to the hardware it is running on, including the pros and cons. This is done with pc gaming all of the time, and to be honest even normal reviews of games expose performance flaws often, and have been since like, forever.
Anyway, it has less to do with rating/reviewing the actual entertainment value, so you need to keep that in mind. If this sort of thing is not for you, just move on. Not like you have to read it, and its dumb to bitch about or get upset over it given its focus is for techies mostly, and it definitely has nothing to do with Wii U bashing, as they are critical in detail on all the systems concerning performance flaws, etc in their articles.