That article tried really hard to try to tie interracial cuckold fetish into far-right political views. No interest in talking politics but that is very much not the case for me, and I'd be surprised if there is much correlation there.
In my opinion, it's this. The vast majority of white guys addicted to interracial porn, and especially cuckold, have a submissive fetish. I'm not small, I'm not bad in bed. I'm tall, in shape, and women are attracted to me. But I have a submissive and inferiority fetish. While I'm actually decent or pretty good in bed with my wife, that fetish causes my brain to hyperfocus on the people that are better because it turns me on like nothing else.
People in general, all people, have a tendency to categorize themselves and others. Race is the most common because it's the most obvious. I can't look at someone and definitively know if they're rich/poor, but you can tell if they're white or black. If your biggest turn on is submissive/inferior, your brain is going to seek a dominant/superior to fixate on to trigger that dopamine dump. Race is the most obvious difference, so for a ton of white guys with this fetish black men become the central theme.
And there are plenty of good reasons for that.. There are certainly aspects of racial stereotyping, but it isn't necessarily incorrect either. The "once you go black..." phrase is a lot older than the interracial porn boom, it become a well-known phrase for a reason. Look at all these dime Instagram models, whether dating or they have a baby, it's almost always a black man. Look at how many white women exclusively date black men, which you almost never see in the reverse, the women on this site that prefer black men. There's a ton of evidence mounting that a disproportionate, and growing, number of white women prefer black men. Obviously not every black man is a stud, but there is no room for debate that black men are, in general, superior athletically to white men. Look at pro or high-level athletics. Penis statistics are out there.
So if you're a submissive whose subconscious is looking for a focal point to your fetish, there is a pretty obvious choice. I'd even go so far as to say there's a right answer, which is what makes the addiction so much more powerful. Sure, there are guys of every race that could fuck my wife better than me. But if you were to choose a man at random, what would truly be your best odds? It's not a random white dude.