I have also thought of it in the other way round, don't we think that politicians who loot government funds can use bitcoins to hide huge amount of money such that when the EFCC want to probe them for mismanagement of funds it will be difficult to recover looted funds since they might not be able to trace it due to the fact that they have converted the money to bitcoins.
It's not really something you have to think about because it's basically something that has been happening for a very long time and is not going to stop either anytime soon. Basically although bitcoin is based on decentralization , you can't really blame the negative uses on the network.
The whole thing is worse for privacy coins like zcash and especially Monero. The government has virtually succeeded in taking Monero off grid almost to totally and they mostly blame it on Monero being used for fraudulent practices.