Re: this is not bias
"at the scale included in the article the image of Obama and not Obama are very comparable indeed."
If you squint and blur your vision, the general shape is very good. But the skin tones are significantly lighter in the generated image. That's the bias showing. Generally, when upscaling or zooming a poor image to enhance it, you want to create new pixels between the larger pixels which are averages of the general area of the image. How you can interpolate lighter pixels between darker areas such that the average across the whole area becomes lighter is beyond me.
It'd be interesting to see what it does to a pixelated image of Trump after he's just come off the sunbed and is at is most "orange panda-like" best. It'd probably put glasses on him :-)