The premise that US-specific algorithmic tuning explains US-specific polarization is unsupported speculation; US-specific non-algorithmic factors (two-party system, partisan media, elite polarization) are more parsimonious explanations.
Cross-national divergence in polarization trends exists despite similar social media diffusion across developed democracies.
The US has distinctive non-algorithmic features (two-party system, partisan cable news ecosystem, high elite polarization) that distinguish it from other democracies with similar platform adoption.
Is there a plausible alternative hypothesis that has not been considered or that would explain the facts at least as well?
Could the facts be jointly explained by a conjunction of weaker causes rather than a single dominant H?
Could the body of facts F itself be an artifact of selection, measurement, or reporting bias rather than a real phenomenon needing causal explanation?
Does H actually explain the full body of facts F, or only a salient subset?
Are the criteria used to judge H 'best' (scope, simplicity, mechanism, prior probability) appropriate for this domain, and are they applied consistently across the alternatives?