The U.S. government doesn't like competition...
I live in the UK, why would the US government interfere with something I use? (Not saying they wouldn't, just curious as to why one government would take exception to an international currency).
Incidentally, the US dollar already gets a lot of competition - GBP, EUR, JPY, CHF, CAD, AUD, XAU, XAG ... etc :-)
Although the US Fed usually has the internet spotlight, don't forget that your own country has a national reserve authority as well.