Kanye is clearly a gigantic jerk but a talented one nonetheless. It's no wonder Macca loves working with him so much. He probably gives him flashbacks to his late songwriter partner. (Although Lennon was more of a jerk than Kanye, seeing as West seems to treat his wife with affection and isn't abusive)
Are we really comparing Kanye's talent as a "songwriter" to John Lennon's now? Oh boy.
Well clearly McCartney respects West enough to continue work with him, and claim on multiple occasions that West was one of his favourite contemporary artists. Unless you consider yourself a higher authority on musical taste than Sir Paul?