It isn't JUST speech that radicalizes people. There are a plethora of underlying material conditions that contribute as well, but nobody here is talking about any of those. We can't just prevent people from saying bad things, we have to address things like education, poverty, inequality, housing, and journalistic integrity before we can just punish insulting sentiments.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6414414/

https://www.start.umd.edu/publication/radicalization-violence-pathway-approach-studying-extremism