Could you expand on this?

The fact he was white and they were black is only relevant because [their target audience] is expected to relate to the boy’s fear of black people.

Yes, it’s used as a bait-and-switch.

In this interview video, one of the interviewees talks about how they (a trans man) and a man dating a Hispanic partner both shared those secrets while they were members of a murderous white supremacist neo-Nazi organisation. This is not, by a long shot, the only similar cases I’ve seen, only the first which came to mind.

In my own country, a neo-Nazi group which tried to register the White Australia Party had a member with Central American heritage in their own flash mob (Alexander Gabriel Mare), and infamously had a love-hate relationship with this absolute clown of a member (fun video, even if sometimes confronting, with a happy ending).

It’s the colour historically associated with liberalism (as in capitalism).

Yellow/Gold is historically the colour representing liberalism (as in capitalism), which has a solid history of ending royal monarchies.