I think it is okay for them to do so. But it would be wrong to track transaction of non-terrorist people. I think you still can bypass this tracking.
And how would they determine who owns what address? How do you know that the person who owns the address you are tracking is or is not a terrorist? Given the pseudonymous nature of Bitcoin, it is pretty damn impossible to determine who actually owns the address.
There's not much they ca do today, but if they asked all their exchanges to provide information about customer's trades, deposits, withdrawals, and IP addresses used they could connect it all to transactions in the blockchain. New York got the Bit License, and Germany could bring in tougher measures if there was enough support for them.