In online comment sections, it is common for netizens to express moral outrage toward norm-violating behaviors. However, how comments rebutting such outrage influence public attitudes remains underexplored. This study examines the effects of different rebuttal styles directed at outraged commenters (aggressive vs. rational) and comment virality (high exposure/viral vs. low exposure/non-viral) on public attitudes through two experiments. Study 1 found that aggressive rebuttals against netizens expressing moral outrage improved observers’ impressions of those outraged commenters (an effect that held across both high- and low-exposure conditions), but had no significant impact on sympathy toward the original norm violators who sparked the controversy. Study 2 found that rational rebuttals significantly worsened observers’ impressions of the outraged commenters and increased sympathy for the norm violators, but this effect occurred only under high-exposure (viral) conditions. The research reveals the differentiated effects of counter-speech against moral outrage under varying expressive styles and propagation scales, providing empirical evidence for guiding more rational online discussions.

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