This isn't really new - the majority of the world has been laughing at the US since he was elected.
It kind of a nervous laugh if you know what I mean.
Nah, it was the straight up laugh directly at him:
Diplomats Say They Were Definitely Laughing At Trump At The UN
Trump, however, insisted later in the day that they weren't laughing at him, saying, "People had a good time with me. We were doing it together, we had a good time."