She doesn't see black guys because that way she's less likely to run into someone that she knows/knows of her in civvy life.
This would make more sense. See it on a lot of Asian girls profiles as well.
Ultimately it is the wgs choice who she sees, no need to sugar coat your racism with lies. Just spell it out. I do not want to see blacks or Asians. Simples
When you say I had a bad experience, that is just bollocks. Bad experiences are not down to race. There are as shoes of every colour and creed