Bitcoin's market cap is far too low to finance a huge terrorist organisation. If it were to happen, rules imposed on exchange (AML/KYC) policies can help to prevent it. It is hard to purchase anything with Bitcoin without exchanging to fiat first.
not to mention that terrorist buying bitoin for their activity would actually support bitcoin, more than bitcoin supporting them
i mean terrorist don't have any way to have bitcoin minus buying, if they were really using bitcoin, right now the price would be higher
I believe it's being used ever since. In the deep web I see some contract killers for hire and you pay them bitcoins to kill me or other person, for example. I've heard some secret ISIS sites in the deep web too and anonymous is on high alert about these terrorist sites. I'm sure they are using bitcoin to fund their cause.