For the benefit of people who read only the headline and not the article:
The story here is that the US government captured Russia's energy weapon, which Russia has been using against US personnel for a decade, and tested it to determine what it does (it causes brain damage). This story does _not_ claim that the US has developed a weapon like this themselves.
It does claim the US went to great lengths to dismiss the victims for a decade, while being in possession of the device. That raises the question of what incentives the US would have to deny its existence. To me, that was the story.
The effects aren't too far off from reports of the maduro raid, though my understanding is that the US just used a standard LRAD