I think very few people who are using the words whore/ho/slut, etc are choosing those words because their dictionary definition fits what they are trying to say. What people are saying with those words is "That woman does not live up to my moral standard and I look down on her." That is why there is no magic number of sexual partners or list of reasons for having sex that indicate when you have officially crossed over into "whore" territory. Every time I have referred to someone as a "ho," it's not because I had any in-depth knowledge of their entire sexual history. It's just another (unfortunate) way of looking down on a woman.
Those Mike Jones lyrics are atrocious, but that's hardly a sentiment that's exclusive to popular music. Since music began, unattractive men in all genres have been singing about the women that wouldn't give them the time of day before they became famous who have since had a change of heart.
"Ho" seems to be a synonym for "woman" in some parts. I feel fairly certain that Mike Jones would casually refer to any woman outside of his family as a "ho" (and not because he's making the usual value judgement).