In August 2022, Kyle Rittenhouse's vigilantism in Kenosha, Wisconsin, resulted in two fatalities and one injury, sparking heightened public security concerns and eliciting intense moral reactions. These moral impulses tend to contribute to extreme judgments of right or wrong, thereby fostering polarization on social media. The phenomenon of polarization, recognized as a component of social cybersecurity, has recently gained attention. This study explores the impact of five Moral Foundations on polarization following vigilantism, utilizing moral foundation theory and vector autoregression (VAR) in the analysis of social media discourse. Our findings reveal that these Moral Foundations significantly influence polarization dynamics. This insight holds implications for both research and the development of practical strategies for managing the societal consequences of polarization on social media.