Not sure about the laws of the Netherland, but typically just because a service can be used for infringing purposes doesn't mean that the service itself is infringing or illegal.  Without such protections, any search engine could be sued for providing functionality that could be used to access copyrighted material.  As a result, it's not enough that they simply provide a directory that contains links to pirated material.

Typically the only way to go after third parties whose services may be used for infringing purposes is if they are actively encouraging their clients to use the services for illegal purposes (ie, the Pirate Bay.  The name says it all).

In almost every country, anyone has the option of sueing anyone else for anythinig.  Filing a lawsuit isn't hard.  The question is whether you have enough of a case to get through the initial stages, which they may not, but just starting it can make headlines if enough people care, even if it isn't destined to last long in court.