First off, your fair use criteria may not apply - we're talking Dutch law, not US law.
Second, "the amount and substantiality of the portion used in relation to the copyrighted work as a whole"
The judge judged that this was about 100%. That's basically the whole discussion. Translation does not mean adding new insights or pages, it's just a transcription into a different language. And I have translated several articles myself, I know there's a fair amount of creativity involved if you want to transfer the meaning of the text, not just the words, but it is limited compared to the creation of the original text (or script). The gist of the articles I translated would have been transferred regardless of who the translator was. And given the very limited amount of text in movie subtitles the creative input is very limited indeed. Much more limited than derivative works like "Larry Potter and His Best Friend Lilly".
Non-profit is debatable, the sites that publish the subtitles certainly make a nice profit off the ads.
Effect on sales: since sales are subtitled, subtitles only apply to movies that are pirated. While you can hardly prove that people would have bought the movie just because it was translated, it's hard to prove otherwise too - and since the FSF was bringing the suit, they had to prove that this was the case. Good luck with that.
I'm not opposed to pirating, but at the same time let's not pretend this type of reasoning will hold up in court. It certainly didn't today.