There's nothing to "fight off", if they end up going with black guys it's because they find them attractive to begin with, and they were going to pick those men over alternatives regardless of whatever else is going on. Same way skinny women don't need to "fight off" the fatties to get our attention, because they weren't gonna get it to begin with (ignoring the guys who go for both), and how lesbians and gay guys don't exactly have to worry about completely-straight people "stealing" other homosexual folks from them for obvious reasons.
If anything, you could see it as bullet dodged of sorts; If you dislike black guys that much, then the fact that a woman picked one over you means that you know she's 100% not your type and never would be, and you can move on immediately to try with someone else who's more attuned to your interests. Why that would be such an issue to you, hell if I know, but I've heard of weirder and pettier reasons before.
Also, pro tip: Racial, national and especially ethnonational rhetoric is a giant waste of time and energy you're better off not burning precious hours of your life focusing on. You could put the time and energy from fixating on that shit into things that'll do you far more good, from learning new skills and languages, to working out so you can lift increasingly-fat women, to actually going out and finding a big white girl who'll want to be with you instead of someone else of a same or different ethnicity. Hell, even just beating your meat to fatties like it owes you money is still better for you and less self-destructive than going down this rabbit hole of nonsense and self-hatred, trust me, been there and done that.