I'm African American and often wonder why we're always all lumped together in one group? I've visited Sosua on occasion, but have mostly stayed away for the last two years because of the exact same element you're referring to. It's more accurately described as a social-economic / class issue than a racial one. Those of us who are better educated and belong to higher social economic classes don't like loud, boisterous and disrespectful behavior either. While in Sosua, I've met other black professionals like myself who are capable of going there and having a good time without calling undue attention to ourselves.
Again, I haven't been over there recently, but if what you're saying is true, and the bars frequented by African Americans were specifically targeted, I can honestly say that I predicted that would happen the last time I was there. I could see the declining quality of the black men visiting Sosua and knew that it would only be a matter of time before steps were taken to discourage them from coming. It would be different if they were spending money, perhaps they would be tolerated, but they are specifically trying NOT to spend money.
However, as to my original point, what you see in Sosua or even in the US mass media isn't an accurate representation of African Americans, it's very lopsided. It would be like me forming an opinion of every caucasian person based upon a trip to West Virginia or rural Texas.