If you think it is that easy, ok.
Maybe? it has been done many times before. Iran, for example, has Americas old printing presses and tries counterfeiting vast sums to buy things and de-value the dollar. The British tried it against America during the revolution. The Nazi's tried it against the British in WW2.
Write "Muhammed is a motherfucker" into the blockchain and you are safe.
lol, bloody brilliant.
A weakness of a group like them are their superstitious beliefs. If you curse the blockchain with blasphemous remarks they may stay away from it.