It's been known for a while... Pals for Life is a guild that intentionally picked African-American sounding names for their group and liked to troll. Leroy Jenkins was one of them, I think Terell Owens was another one, and so on.

The "story" was that Leroy was tired of waiting for the raid and left to go get chicken. When he came back he just decided to go and everyone else followed him in. That's why his team says "you are just stupid as hell" and Leroy says "at least I have chicken" at the end. The Viral raid video is really just a racist caricature.