it is not true and it will never happen.
That is one reason why bitcoin is not yet legal, because this is one of the government's fears
What do you mean "bitcoin is not yet legal"? You can buy it, use it, sell it and not face any legal ramifications. The United States IRS recognizes it as an asset and taxes gains on it.
Just because the government has not adopted it as a currency they choose to use does not in any way make it illegal.