It appears that the intention was to trick the safety system into thinking there's a train blocking a railway section, not to derail the trains at full speed.
The one train that was damaged was moving at lower speed because it had received a warning.
Angry farmers are the prime suspect at this point, according to media reports. That makes sense given their usual levels of recklessness, e.g. a few weeks ago two people were killed when they crashed into a traffic jam that formed, even though the tractors only used the right lane. Today they lit hay stacks on fire, hurting visibility for cars.
So they show reckless disregard for life, like XR, but it's not quite terrorism. Neither seems to be interested in receiving sympathy.
https://www.prorail.nl/nieuws/sectiestoring-veroorzaakt-grote-hinder-voor-treinverkeer-in-midden--en-noord-nederland
