Is it impolite to discuss cognitive differences between liberals and conservatives?

Hibbing and colleagues argue convincingly that liberals and conservatives differ in reactivity to (negative) stimuli. Yet their analysis sidesteps evidence that cognitive ability differs as a function of ideology. Cognitive abilities, like cognitive preferences (e. g., structure needs), shape whether stimuli are psychologically threatening (prompting avoidance) or offer opportunity (prompting approach). Incorporation of these findings is critical despite any socially "delicate" implications.