*stepping in
To those using Harvey Keitel as an example of a white pimp: Taxi Driver is a movie.
I'm surprised by people's overreaching PC attitude here. When you think of a pimp you think of a white person? I call shenanigans on that.
*stepping out
Now THIS is very telling ... cognitive dissonance at work

And I mean zero disrespect when I say that ... I know pointing that out to someone is usually negative and they either deny it or take offense on average, but I'm meaning it in a neutral way.
Not at all. The comment about pimp-hats plays on a racist cultural stereotype, you don't need to agree with the stereotype in order to notice when it is being referenced. Do you think for a moment that eth comment about him wearing a pimp-hat would have been made if Cain was white?
I don't, because the imagery plays on the idea of an extravagantly dressed, black, pimp (a stereotype which has been in American culture since at least the 1890's) doesn't work the same way with a white politician.
Again .... I'm thinking context is key, per the person using the phrase or the one interpreting it.
There are some words that are derogatory across the board .... idiot, stupid, m-fer, etc. Others have lost that context, and I might even say there are some communities where words are used and the ones using them would NEVER associate it with the derogatory contexts it's used elsewhere.
"Fool" is an example of such a word. I have only once in my life that I can remember associated it with something negative, because I have grown up where it was tossed around extensively similar to saying "bro" or "dude".
Pimp is the same for me, and others clearly.
I do find this fascinating though that "both sides" can be right about whether it's racist or not. But yes .... I do think that the comment could still have been made even if Cain were white. And here's the thing ... even if you ASK the friend directly if he meant it racially, and he says "yes" ... that is again how he was meaning it in his context. Someone else could have made the same comment (i.e. me for example) and not meant any racial connection at all ...
Finally .... you know what internet memes are "popular" ? Stuff like this:
This guy is the King of Dudes.
And stuff like this:
So the association with being pimped out, or even gangsta .... is being projected onto the affluent whites and such of previous eras. It started out that people were doing it for the irony and the lolz, but even amongst my group of friends .... if they point out someone is pimpin or they make some gangsta style statement, THIS IS WHAT THEY ARE REFERENCING NOW .... they are associating it with some Victorian era or colonial type of dressed member of the aristocracy because it's funny.
And in fact, the first thing I pictured in my mind when the thing about Cain and wearing a pimp hat was mentioned, were those versions of lolz right there ... I would have assumed they made the comment because he's part of the "upper crust of society" compared to the rest of us, similar to popular memes.
It's CONTEXT and the Zeitgeist I'm telling ya lol ...