Well, he probably doesn't have a reason, but I do. I hate the game because my brother played it, and when he played it, he would shout and scream at the TV screen everytime he got killed.
He pretty much became a toxic person, until the game got taken away from him.
Also, there's a scientific article that Fortnite was purposely designed to make people rage, just so that they can continue playing it and spend some more money.
Yeah, EpicGames is evil