We don't know if that is right because right now using technology nothing is impossible regarding of that. As I think yes terrorist can use bitcoin or any cryptocurrency for their findings and we didn't know that is for terrorist fund because right now bitcoin was using any individuals for funding and any transaction. Even banks terrorist can use it so their is no limitation or security regarding terrorist funds.
I think terrorists have mastered the technology that allows using bitcoin to facilitate transfers between them or funds from sympathizers to carry out their actions. This makes it possible to escape the reach of the legal apparatus because bitcoin is anonymous, whereas if it uses banking services it is easy to track who the sender and recipient are.