Oversimplification
Humans are tribal primates running on coalitional software, and the software treats inconvenient facts the way the immune system treats a transplant.
The passage uses a vivid biological analogy — "tribal primates," "coalitional software," immune rejection — to compress a genuinely contested and multi-causal psychological phenomenon into a single, mechanistic explanation. By framing motivated reasoning as hardwired "software," the analogy implies the behaviour is universal, automatic, and essentially fixed, foreclosing the reader's appetite for the considerable nuance the research actually contains.
The 'tribal primate running on fixed coalitional software' framing overstates both the universality and the automaticity of motivated political reasoning, obscuring substantial individual, contextual, and cultural variation that the empirical literature documents.
Research by Tappin, Pennycook, and others has shown that accuracy motivation — simply prompting people to think about whether something is true — meaningfully reduces partisan misperception, which would be impossible if rejection of inconvenient facts were as reflexive and total as immune rejection of a transplant. Further, work by Kahan et al. on 'identity-protective cognition' itself shows the effect is strongest among the most politically engaged and numerically sophisticated respondents, not uniformly across the population — the very opposite of a species-wide firmware limitation. Cross-national studies (e.g., Guess & Lyons 2020) find significant variation in partisan-motivated reasoning across democracies, suggesting institutional and media-environment factors shape the behaviour at least as much as any evolved cognitive architecture.