This chapter examines the historical and intellectual foundations of the diversity, equity, and inclusion (DEI) movement and the controversies surrounding it. Originating in the US civil rights movement and influenced by European postmodern philosophy, DEI has reshaped organizational cultures by challenging traditional notions of meritocracy, free speech, and professional qualifications. DEI policies have served managerial interests by broadening the talent pool. However, their emphasis on systemic racism, unconscious bias, and equity-based outcomes has provoked both support and backlash. The chapter contends that both radical advocacy and rigid opposition fall into ideological fallacies that undermine constructive dialogue.