Othering seems to be an inbuilt mechanism that, once triggered, is very strong and can overrule all empathy with “the others” viewed that way. Cognitive dissonance seems to be rationalized into oblivion. It seems to work at all levels.
I’m pretty sure that I’ve seen it personally in otherwise decent people who supported a specific football club and in people that turned completely xenophobic.
Discussion with the affected people and any nuanced exchange of viewpoints with them becomes completely impossible.
Looking at history, the social sciences and current events, nationalism seems very effective in triggering othering. I wonder what it takes for people to become affected, since certainly not everybody falls victim to it.