In social psychology these days it is commonplace to read or hear that liberal‐leftists and conservative‐rightists are every bit as “moral”; prejudiced and intolerant; susceptible to misinformation, “fake news,” and conspiratorial thinking; lax about upholding democratic standards; and prone to terrorism and political violence. Upon careful inspection, however, I conclude that every one of these claims is false or misleading. Liberal‐leftists in the United States and elsewhere are demonstrably more committed than conservative‐rightists to humanistic‐egalitarian values, deliberative reasoning, and adherence to democratic norms. In Western societies, acts of authoritarian aggression, hate crimes, and political violence are overwhelmingly more likely to come from the right than the left. As a witness to Nazi atrocities, Kurt Lewin deeply understood the role of historical, economic, and political forces in human lives and the interdependence between democracy and social science. He rejected moral relativism and what I call “both‐sideology” and offered a sophisticated critique of anti‐democratic tendencies. There are perfectly understandable reasons why people—especially academics and journalists—would be tempted to draw parallels between the left and right, and indeed there are many similarities as well as dissimilarities between liberal‐leftists and conservative‐rightists. However, the uncritical adoption of both‐sideology threatens liberal democracy itself and, with it, the only social science worth having. What we—as citizens and social scientists—need now is a renewal and revitalization of Lewin's critical‐emancipatory legacy before it is too late.