Your link explicitly refers to the use of IMG2IMG: the AI isn't stealing anything. Rather, the example is nothing worse than pasting something into Photoshop/whatever painting software, touching it up, and claiming it as your own. Indeed, it's awful, but has nothing inherently to do with AI.
In addition, if you didn't know, you can't train models using IMG2IMG, and, neither would such a feature be possible or advantageous. Thus, the only process which could possibly be considered as 'stealing' on part of the AI would be the initial training, which this does not refer to. (For convenience, I've already addressed the initial training in my former comment.)