This paper studies how online discussion shapes and assesses political violence across different settings, particularly how moral evaluation, as a social perception, varies across institutional contexts. We take France and the United States as case studies, both democracies, and three incidents of political violence: the 2020 killing of Samuel Paty in France, the 2025 shooting of Charlie Kirk in the United States, and the 2026 murder of Quentin Deranque in France. Using publicly available posts on Instagram and Facebook, we use GPT-4o-mini for zero-shot classification and social network analysis. Our research demonstrates clear cross-national differences in how moral values are perceived, the emotional intensity expressed, the framing of institutions, and the structure of semantic networks. In France, the discourse tends to focus on the victim's civic role rather than their political affiliation, whilst in the U.S., the conversation is more ideologically divided, with moral judgments frequently reflecting partisan lines. By comparing the two French cases -- a civic victim (Paty) versus the politically-affiliated victim (Deranque) -- we find evidence consistent with the \textit{civic floor hypothesis}, which demonstrates France's institutional framework upholds a cross-partisan civic baseline regardless of the victim's political ties. We conclude by analyzing the implications of computational social perception for multilingual NLP and by exploring moral judgment in cross-national digital political discourse.