It didn’t matter that ALL 50 governors objected to this concentration of power in the hands of the executive – the Congress simply moved forward by changing the balance of powers through legislation
And from the Constitution (Art 1 Sec. 8) :
Congress shall have the power ...
To provide for calling forth the Militia to execute the Laws of the Union, suppress Insurrections and repel Invasions;
In the case of natural disasters, they are Executing the Laws of the Nation. Congress makes those laws.
But the National Guard hasn't been a true state militia for around 100 years. Every member, and I was one, is also a member of the federal reserve of the appropriate service, Air Force or Army. The ID card carried by a Guardsmen, is identical to that carried by a member of the Reserve, which I also was a member of before and after being a Guardsman. The states do not pay the Guardsmen, except in those rare instances when they are called out for state duty. Even then the feds often pay, but not from the same DoD account. Not even the full time cadre. The only exception is the state staff, the Adjutant General and his staff.
If we had a real President, he would be calling them out to repel this invasion, instead of instigating it. This is one of the reasons the Constitution provides that only a Natural Born Citizen can be President. Obama isn't one under the meaning of the term understood at the time the Constitution was written and ratified. (Unless B.H. Obama, the Kenyan drunk wasn't really his father) Thus he's not a real President, and his actions reflect that.