In the US, neither the left nor the right could be considered 'anti-authoritarian', as the left embraces broad government control of economic matters (a welfare state, environmental regulations, relatively high taxes), while the right embraces government control of social matters (regulating abortion, supporting 'traditional' marriage, etc.)
If you had a country with a perfectly free (laissez-faire) economy, but with strict social controls (mandatory Christian prayer in schools, abortion punishable by jail time, and mass deportations of illegal immigrants) leftists would call it an authoritarian nation.
If you had a country with a state-controlled economy (complete with cushy welfare state!), but with perfect social freedom (legal drugs, no regulation on abortion or sex work, and open migration) the right would call it an authoritarian nation.
While both right-wing and left-wing governments can exist without crossing the line into authoritarianism, only the classical libertarian's ideal government is by definition anti-authoritarian, because its focus is on the consent of the individual, whereas others are satisfied with the consent of a majority.