Your reader's defense of Mo'Nique was nice but erroneous. Large black ladies have never been "vilified" in this country. Made fun of and stereotyped, yes, but not "vilified."
The notion of the strong Black Mammy is one of the most positive portrayals of Black folk in the US going back to slavery times. And there was nothing "cringe-worthy" in Hattie McDaniel's portrayal in "Gone With The Wind" -- she was in complete control. In fact, her portrayal was just about the only positive portrayal of Black people in that movie. And, yes, Mo'Nique's award acceptance speech was extremely self-conscious, self-aware, and self-important.
I don't know about smug and self-righteous, but it certainly made me do a double-take when the first thing she said was that her win was about the performance and not the politics, and then almost everything that followed made her win all about the politics.
Not to mention a teeny bit arrogant and ungracious to assert that yes, she was better than the other nominees. Maybe that's what you meant by self-righteous. (Rule No. 1: you don't applaud yourself; Rule No. 2: smile, if wryly, when they call the other guy's name; and Rule No. 3: whatever you may privately think, it's very bad form to say that yes you were better than the people you beat.)
And maybe I'm too post-something-or-other, but why can't it be just about the acting, or the direction? Is it really so much based on the gender and the colour? I'm glad Barbra felt vindicated somehow for her Yenta loss, but I think it demeans Kathryn Bigelow to make her win about her gender and not her undoubted talent and skill, and to imply that somehow the Academy has decided to give a woman director a turn, and an African-American Best Supporting Actress a turn, etc. It's all contradictory anyway: it's either about the work or it's about the politics, and you can't have it both ways.
Your reader is wrong. She's the fourth black woman to win Best Supporting Actress: Hattie McDaniel (1939 - Gone With The Wind), Whoopi Goldberg (1990 - Ghost), Jennifer Hudson (2006 - Dreamgirls), Mo-Nique (2009 - Precious).
I'll tell you what was wrong with her speech. And a quick survey of the comments on Bossip, a black gossip website, shows that there are plenty of blacks who agree with me. When she named Hattie McDaniel it was as if she forgot that black actors and actresses have been paving the way for her success for decades now; it's not like there was Hattie McDaniel and then all of a sudden Monique. I think that tells you a lot about her frame of mind.
Samuel Jackson's eye-roll said a lot.