I don't think they are stupid, they are trying to protect their insolvent banks. They've just passed a law allowing banks to transfer people's savings to the capital assets of the banks. Merkel has just ripped off Greece to try to save the dying German Douchebank, who has the largest exposure to junk derivatives of any bank. Of course they want to stop people using Bitcoin as a store for their savings.
They are stupid, because you can't stop people from using anything, it's their right, their freedom, their independence to do whatever they wish to...
They are paying taxes to live there, paying bills and everything to the government, so you can't say government isn't getting anything from them...
Bitcoins aren't anything that's related to some terrorism or some bad things due to which they are stopping everyone using it...