I'm not sure what XXXTentacion has to do with it, but afaik the trend didn't start with him.

Worldstar Hiphop is a video sharing website that, to my knowledge, markets itself heavily to poorer/urban communities. One popular trend that the website has gotten stereotyped for, is that people often upload videos they took of other people getting into fights (which I've heard from some is a popular point of entertainment in certain low-income areas, but I could be wrong on that and I don't want to offend, so feel free to correct me). A common trend is that when a fight breaks out, someone starts recording it, and shouts "Worldstar!" which is more or less shorthand for "I'm recording this and it's going on Worldstar!" The meme spread from there where people will say it when two people get into an argument/fight, or when some general stupidity happens.

yo