In Zara vs indie designer, Zara steal the design and uses its power to distribute and sell it to the whole world. The indie designer cannot compete, or fight. The fact that Zara used her designs will not advertise her own products or make her money (maybe it did after the public outcry, but I guess it will not be the case for every indie designer).
In torrent website vs content producers, the torrent website or its user are not more powerful than the producers. They do not put the producers' business at risk. Everyone knows who made the original product, and may buy some genuine products or derivatives : torrenting can act as advertisement.
One of the other justifications for torrenting is that the content is not available in your country. Similarly, the indie design was not available in all countries. But the source of the issue is different : a small business may not distribute to the whole wold because of logistics, whereas producers and distributors voluntarily block content from being available when it could be.