You have raised a valid point about there being a more PC way to determine the type of client/date. For the professionals (escorts/masseurs) I could see something like "Client preference: Caucasian only"; and, for dating sights, "Seeking Black/Hispanic only" along with age/weight restrictions.
For as long as there are humans there are going to be racial barriers, and it would be a huge positive step forward for everyone if harsh disrespect could be replaced with more diplomatic verbiage in public advertising.