The positive side of prejudice is protection of the tribe.
It’s nature’s way of alerting us to possible danger when someone unlike us enters are space.
It’s human nature and the nature of every other animal. It’s written into our DNA.
It’s a survival mechanism.
The new kid on the block is always treated with skepticism, until the new kid proves to the others that he/she can be trusted. And newcomers are just as wary. We, as humans, all know this.
So don’t be so trigger happy with the prejudice label, or when someone doesn’t invite you in as one of their own. With people moving around much more than they did in the past, skepticism and wariness abound on all sides.