The website explained they had received the clip - which was shot backstage at a promotional event - four years prior to that but decided not to post it because of Justin's age and because he "immediately told his friends what he did was stupid."
After it was published, the Canadian singer apologised for his "inexcusable mistake".
He said: "As a young man, I didn't understand the power of certain words and how they can hurt. I thought it was OK to repeat hurtful words and jokes, but didn't realise at the time that it wasn't funny and that in fact my actions were continuing the ignorance.
"I take my friendships with people of all cultures very seriously and I apologise for offending or hurting anyone with my childish and inexcusable mistake. I was a kid then and I am a man now who knows my responsibility to the world and to not make that mistake again."