well, I don't really buy into this hype, it just doesn't add up.
First, I don't see why kissing in a movie is causing havoc, but kissing behind the scenes, like he did with Julia, is okay. Makes no sense to me.
Second, I haven't seen him having tons of steaming love scenes with black women either. When it comes to love scenes, he is probably the most asexual actor in hollywood, period.
And lastly, the total black population is 12.8%, with some more women than men, so lets estimate a black women population approx. around 8% of the total US population. I don't see how some hang ups of ~8% (minus the black women who are too young or to old to go to the movies, minus the ones who don't oppose interracial couples, ect.) are going to make or break an actors neck. That's simply not realistic. In this context, I found an interesting assertion in an article about the same issue (Seems like his "reasons" turn like flags with the wind):
Washington, the most potent (and bankable) black screen actor of his generation, has always been sensitive to the racial dynamics of the American marketplace. While filming the 1995 film Virtuosity, Washington — the son of a Pentecostal minister — refused to kiss white co-star Kelly Lynch. During an interview in Jet magazine, Lynch later suggested she had no trouble with the scene, “but Denzel felt strongly that white males, who were the target audience of this movie, would not want him to kiss a white woman.”
Whole article here
If you ask me why some black actors have more success than others, then I would say that it has of course to do with his talent and with the quality of the movies. If you look at the movies Denzel is performing in, then it's pretty obvious that a Denzel in the cast is always a guarantee for a high class movie, that's not always the case with, for instance, Snipes.
Over here, Denzel is one of the highest rated actors as well, and people over here really give a shit about the color of someones love interests.