1) Women putting **** in their mouths--everyone loves seeing women putting **** in their mouths
2) White women--everyone loves white women
3) Unattractive white women--this is the biggest one. The fact these girls are not conventionally attractive is what makes it artistic. If they were, this would just be another example of 'hot girls doing weird ****.' But these girls aren't hot. So this can be considered more tasteful, less trashy, and less degrading to women.
Not seeing what was so unclear about that.