I’m not sure why this is surprising to people, it’s the reason why first impressions are a thing. Most people aren’t heavily biased towards any side of most issues, it’s the personal encounters that often force it a given way. Hell, even if you realize you still need to respect X, you are less likely to stand up for X when this happens. It doesn’t really help X that X is essentially making the same argument for itself, “treat X with respect” while that person doesn’t feel the respect returned.