I bet people really popped off when Kanye tweeted this. What's the point of calling out the word "bitch" when you use the word so profusely? I'm not saying I have an issue with it, even though there's a legitimate discussion around the word. I'm just saying, why would someone knock something that they actively do. Case and point, "I made that bitch famous." Let me tell you why. It's because he's talking about the time and the culture.
When Kanye West says that Stevie Wonder never had to use the word bitch, he's not talking about Stevie Wonder's innate abilities (although Stevie Wonder is fantastic). He's talking about the current time and culture of black artists versus when Stevie Wonder was at his height. At least that's what I think he means... who really knows.