People's negative reactions to Emilia
When people react negatively to Emilia for being a white-haired female half-elf, the story seems to portray this as just prejudice. However, given what we're shown of the Ordeal that Petelgeuse puts on, it would seem that whenever there's a white-haired female half-elf that the Witch Cult will eventually show up and slaughter everyone around her. If that *is* the case then it would be rational to want to stay away from Emilia and be afraid when she shows up. And since people wouldn't know *why* the Witch keeps doing that, it wouldn't be entirely irrational to hold some suspicion of any white-haired female half-elf you meet.