You are making a character assessment based on your own biases. There are no studies or statistics that exist to back up the likelihood that she would interact with or run into any “genuinely nice white people.” The mythological invented concept you have dreamed up known as “genuinely nice white people” is literally a Harry Potter level magic guess about who people are when no one is looking. It was very Dumbledore of you but not much of anything else.

Just like I would never alter my behavior based on the belief that there are “genuinely nice black people.” You are asking her to alter her thinking patterns to anticipate a run in with a mythological group of “genuinely nice white people” she may not or never run into.

Even if Matthew, Mark, Luke and John were present to bare witness to the twelve disciples this does not mean that everyone in Judea would have theoretically run into “the genuinely nice 12 disciples.”

How could a rational individual possibly purport to know this information? That this yet statistically unproven group of genuinely nice white people exist?