The reason for US anger is Iran not asking for permission
The president of the United States said some days ago that they will put pressure on Iran so that the people of Iran come to the conclusion that following their nuclear activities is useless for them. This means that when the Iranian nation achieves a technological breakthrough, like nuclear energy in their opinion, other nations will be so encouraged and they will believe in their own abilities. If this happens, western powers will not be able to control this. They do not want to let this happen. Of course, they interpret the issue in a different way in order to stop our progress. They say that they are afraid of a nuclear bomb, but they themselves and many other people in the world know that they are lying. They are not concerned about a nuclear bomb. They know that Iran is not after building a nuclear bomb, but rather Iran is after acquiring and developing nuclear technology. That is why they are concerned. A nation has managed to make huge progress on its own while it has not asked for their permission and it has not begged them for their help