If I remember correctly the USA was similarly "deeply concerned" about Honduras and Paraguay.
The deep concern rests on considerations of public perception in the states that are the beneficiaries of America's largess. America does not connive in the overthrow of democratically elected governments.
Unless there's something in it for America.
In Morsi's case, it was obvious all along that relations between the Muslim Brotherhood and the US were something less than brotherly.
Going forward, one has to wonder how this turn of events will impact US relations with Qatar and Saudi Arabia, the two most indefatigable supporters of Islamic fundamentalism, and both US allies/proxies.
There will be interesting times ahead!
By the way, who do you suppose paid for that obviously pre-planned fireworks display in Tahrir Square tonight?