You might be right, but I do not think that is the case.
In my opinion, the scenes she does with her husband are usually good or very good. The threesomes they did with the white guy (or guys?) they were all VERY good.
The ones with the black guys though... they were quite bad. Perhaps the guys did not have their best day or perhaps they were simply bad choices. I do not know, but seeing the results I would prefer that she did not repeat with those guys because the results speak for themselves.
But if we are going crazy with theories, perhaps she is simply not into black guys and she is doing these scenes due to 'internet pressure' and precisely because she does not like it, the results are these? I dunno man, but this is just a baseless speculation.
In any case, I hope nobody gets defensive for my opinion (this is the Internet, so you never know, but I am speaking out of pure honesty and with all respect to all preferences). This are just my two cents and I do not claim to be an universal truth. Take it or leave it. This is a forum, so I guess all opinions are valid, right?
Cheers.