It's not just that they are fed up with the slander.
The FTD software used to have what they called an 'NZB Button'. On the page with the information about the content you were looking for (filenames, size, description, etc.), there'd be a button which if clicked on directed you to an external usenet search engine, with the correct search terms already filled in. After talks between FTD and BREIN, FTD decided to remove this button, and to not allow their users to post direct links to nzb files, or nzb search engines. FTD did this to prevent BREIN from coming after them, they are not linking to any content whatsoever anymore. There's just users telling you what filenames to look for in which newsgroups.
So, here's FTD talking to BREIN, agreeing on taking these actions, taking away any shred of doubt that what they're doing is completely legal under Dutch law, when Tim Kuik comes along and happily continues to call them criminals.
In all fairness, there are third party plugins to the FTD software that re-enable this NZB button, but those are beyond FTD's control.