Final answer:
Original MCs and DJs were upset by "Rapper's Delight" because it signified a departure from hip hop's foundational practices, highlighting the concept of stimulus diffusion, where the essence of a cultural form changes as it spreads and is adopted in new contexts.
Step-by-step explanation:
Original MCs and DJs were upset by "Rapper's Delight" because it represented a shift from the traditional hip hop roots where DJs created music from vinyl records, to a style involving trained musicians for background music and beats. This change exemplifies stimulus diffusion, where core elements of a cultural practice spread but undergo significant modification by new adopters.
Rapper's Delight, created by young men from New Jersey, differed from the Bronx-originated hip hop which utilized DJs and prioritized anti-gang messaging, as seen in the works of hip hop pioneer Afrika Bambaataa. When hip hop culture spread to locations like Los Angeles, it further evolved into styles such as "gansta rap," reflecting local conditions and preferences.
Additionally, the 1980s saw a media portrayal of black America heavily influenced by these modified forms of hip hop, painting a stereotypical image criticized by figures like Chuck D. This resulted in a national dialogue on racial prejudice and multiculturalism, as seen in Spike Lee's film Do the Right Thing.