Allport believed real group differences exist but get distorted and weaponized by prejudice.

Evidence

Allport argued that there exists a core of actual group differences which become magnified by prejudice so that the resulting stereotypic beliefs about outgroups are more extreme, negative, and overgeneralized than warranted by the data. … The prejudiced person then comes to invoke group differences as a justification for his or her prejudiced attitude (see also Jost & Hamilton, ch. 13 this volume). According to Allport, “Difference alone does not make for hostility … and yet the prejudiced person almost always claims that some alleged difference is the cause of his attitude” (1954/1979, p. 87). — , Rudman, Laurie A - On the Nature of…, 835

Categorization

• XREF: Relevant to contact-theory reassessment claims about accuracy of group perception; also echoes system-justification (Jost) chapter cited.
• QUESTION: Modern accuracy-of-stereotypes debate (e.g., Jussim) challenges the ‘distortion’ premise here — worth chasing whether accuracy researchers misread Allport this way.
• corroborated: 2 independent passages support this claim — , Rudman, Laurie A - On the Nature of…, 835