According to all the story lines I've seen, the Baby of Steel was found in his crashed space-ship and adopted by an American family and raised here. That's why it's "Truth, justice, and the American way"—besides the fact that the American way is better, especially in America, where virtually all the stories take place.
So now he's a traitor. Load up the kryptonite gun and get 'er done.
Maybe it will turn out the UN-slave Superman is really an impostor-robot created by George Soros's lab. And the real Superman will break out of his kryptonite-walled prison and destroy the impersonator. Which I look forward to after bankrupt DC Comics is bought by Roger Ailes.
Actually, in the story in question from Action #900 Superman notices (while having the conversation with the government official) that there are Marine snipers armed with kryptonite bullets only 200 yards away...and then points out that camouflage uniforms don't hide someone very well from someone who can see into the infrared, ultraviolet, and x-ray spectrums.