If every Spaniard I meet kicks me in the nuts; and every Belgian I meet gives me a cold beer, eventually I'm going to prefer the company of Belgians over Spaniards.
Is that discrimination and prejudice?
Social groups need to look after their collective reputation, rather than demanding we refuse to learn from our experiences.
Yes. But is it warranted? Yes. We learn lessons from our experience - for better and worse. And even if only one in ten kicked you in the balls, you would be on guard 100% of the time. We should learn to be wary more often these days - as people are less trustworthy and more likely to be looking to gain for themselves, even if it costs others. Pretending it isn't true, doesn't stop it from being true.