The so-called indigenous are immigrants too.
People like to wander, discover, and crave new adventures. They’re not coming to build a country; it’s already built. They’re a little late to the party so-to-speak.
Most people here now are born from separatists, people who didn’t, or didn’t want to, fit in where they previously lived. It’s no surprise that they exhibit separatist traits. Those wanting to live here illegally (or outside the law) are also separatists. They have no plans to integrate.
People are by nature suspicious of strangers for survival reasons. Would you let a stranger walk into your house or backyard? Many people think of America as home. They fear people they don’t understand. You can’t just call somebody a racist and expect that ‘uncertainty’ to disappear.
In fact, those who scream obscenities and slurs and isms and ists at those who want everyone accounted for in the country where they live, raise not lower that fear level.
There is as much so-called racism in countries where there is the greatest diversity. In the Middle East or Africa or India where people are pretty much the same, they find other reasons to shun people who otherwise look and act like themselves.
I don’t see any mystery.
Understanding something doesn’t equal condoning it. If nothing else, it lowers somewhat the anxiety level of the individual, group and ultimately the masses.
When some group wants to excite the masses, they usually start rumors they know in advance will have that effect.