because he's ridding the beat, ha. :lmao:
the different voices and vocal effects enhance the lyrics, and provide the rhythm - which along with melody, is the core essence of the track. there's definitely a school-like cartoonish quality to it.
it works on many levels; you could take it seriously as a way of overcoming pain, or you could use it to laugh off the absurdity of each situation presented. genius work. his best in my opinion.