This isn't true. Private currencies exist(ed) and are afaik still legal.
The reason we put governments in charge of our money is that up until about a decade ago it was either the government or a corporation as a decentralizes currency was not really implementable. Do you want to get paid in amazon coins only redeemable on amazon? No, you do not.
>interest rate meddling by govt contractor federalreserve
You need to do that. Any currency needs some mechanism to control issuing. If not the government who else could do that?