Isn't bitcoin's usage suppose to discourage them due to this control loss?
It should, but if (and it's obviously a huge "if") the US government ever did adopt bitcoin, I am certain they would set up various agencies with the goal of attempting to rig the system in their favor or exert some sort of control over bitcoin. Whether or not it all worked would probably depend on whether or not people allowed them to do so. We already know some centralized exchanges run fractional reserve systems with their customers' deposited bitcoin and do not hold everything they should be holding. No reason the US government wouldn't do the same.
At this point everyone can create money out of thin air as long as there's trust to this person. So, the root of the problem is the banks' policy. This 0% reserve requirement is disgrace. How's the things there in USA about this? Is there concern from the citizens?
There is no concern because hardly anyone knows about it, and the people who do know about it don't understand it. As I said above - banks have always been able to print more money at will by creating new loans. Whether the fractional reserve rate is 10% or 0%, this doesn't change. Reserve requirements are (or were, before we moved to an "ample reserves" model) a way for the Fed to influence interest rates and liquidity by requiring banks to loan money from them at end of day to meet the stated requirements; they were never a method for the Feds to regulate banks' activities or dictate how much they were "allowed" to lend.