Yes, human beings are tribal. We tend to react with suspicion to those who hold themselves apart or behave in ways the majority culture consider odd. Peer group pressure is a powerful tool of conformity and those who resist will face sanctions. However much we might pretend otherwise, it's the nature of the beast within us.
Some cultures have developed more authoritarian and conformist tendencies than others but most express sanctions against the outsider, even if it manifests just as a low level distrust. So yes, in some respect it is their fault. It would be nice if we, as a species, were more accepting but. We. Just. Aren't. We, as thinking liberals, can recognise the impulse and move beyond it, but I think history shows that, across populations, the veneer of civilisation isn't quite as robust as we might wish.
Now, in saying that I am not saying it is their fault, even 50%, merely that over time minor differences will be exaggerated, both by the minority as a signifier of proud difference and by the majority as an excuse for discrimination. A perfectly human tendency kinda makes things worse.
So, does it matter which way round we look at it ? What's done is done and we need to move forward more urgently than we need to explain past grievances. Both sides need to recongise that there is a problem and each played a part in creating it and each has apart to play in fixing it. Right now I don't see such recongnition by either group.
Yes, there are a lot of individuals who have assimilated. Group tendencies don't preclude individual variant behaviours. I dson't necessarily see a great difference between our positions except mine is perhaps a more brutal acceptance of how people are. keep to the Fen Causeway