Rihanna's mother, Monica Fenty, isn't in the public eye very often; in a rare public appearance, Fenty presented her pop-singer daughter Rihanna with a lifetime achievement award at the American Music Awards. And then Justin Timberlake mocked her onstage as the crowd clapped.
Fenty is from Barbados and has a Bajan accent, one Timberlake affected as he took the stage, saying "How cute Rihanna's mom is! She's so proud of the icon!" (A video of the incident is here.)
Pop music lately has implicitly and explicitly co-opted the tropes of historically black genres in order to mock black people; a white soul singer using his award acceptance speech to laugh at how a black woman talks is a particularly ugly iteration of this. (The show also featured pure racial appropriation, as with Katy Perry's geisha-themed performance.) Her daughter's success aside, Monica Fenty has less cultural capital than Timberlake; she was an outsider at the ceremony, brought there to provide a cute moment -- or, if you're Timberlake, an opportunity for cross-cultural mockery. Timberlake wasn't taking a shot at one of his equals, which would have at least felt like playing fair. He was picking on the one person onstage the entire night who wasn't famous, who was just there to celebrate.
The strangest aspect of the whole thing is how sensitive Timberlake is to jibes directed at him. Later in the evening, the comedian Sarah Silverman drew attention to Timberlake's race, joking while presenting an award that he and Thicke were unusual contenders in a "soul/R&B" category. Said Silverman, "I don't know who will win, but I do know who should find this most ironic if she loses." (The only other nominee was Rihanna.)
"Growing up in Memphis, Tenn.," Timberlake replied, "I can honestly say that's the first time I've ever been racially profiled by a white woman." He ought to chat with Monica Fenty about how it feels!