Bitcoin is not illegal in the USA. This means it is accepted. Even the US government has made money selling bitcoins... how does this mean it is not accepted??? Please clarify yourself because your first statement seems to be very wrong indeed.
If any major terrorist attack gets funded by Bitcoin use due to decentralization and anonymity, it's
GAME OVERTerror group ISIS, ISIL, Al-Qaeda have some 20 countries.
Yes bitcoin can be use for that purpose but who funded the terrorist 10years ago? I think its not good to pin point this kind of situation to cryptocurrency cause I believe well known people support at least one terrorist for their protection. We cannot stop that anymore accept it. Cryptocurrency are still not recognized as legal in many countries though its accepted but not fully legal.