Interesting post. Being Half black and half white I guess I see things in similar manner. My new Aunt, Uncle married her, lives in MS, is black with a PHD. She is very well spoken and educated. In fact, on our recent trip to MS (2 weeks ago) my wife(mexican) never knew a life existed. We went bowling with them and there was 2 white people in the entire place, one being my mom the other being her sister. In So Cal, there isnt an abundance of any 1 race. We are a melting pot if you will. My biological mom (white), married my dad (black), adopted my 2 sisters (mexican), and my adopted brother (black / mexican). I also have a brother from my moms first marriage (all white) and my full brother (black and white).
I’ve experienced racism in most of my relationships despite being half white. It was always a struggle because I could never really understand it being we had almost all races in our family and a military dad. The nice thing about the south is that it’s “in your face” racism. You know who is and who isnt. Out here it is very different. You really have no idea until a whisper gets out.
In your case, you should be suspicious of who lives with you. I know I would for sure. However, I’d look a lot more into it than a first impression. Education, work experience and similar interests.