the joke it self is still racist it doesn't matter if it is a black guy or white guy who first told you the joke.
Its a RACIAL joke, in my mind, not a racist joke. It concerns race, however it doesn't inherently suggest there should be prejudice towards a particular race or that one race is more superior/inferior. The person saying it CAN be racist, its INTENT, can be racist, but its not magically "racist" because it deals with racism or uses a term that is often used with racism.
Its a Racial joke that deals with Racism. You could have two different people telling that joke to two different groups and likely get laughs for ENTIRELY different ways, which just shows how jokes are not always the same no matter context.
Get a black guy saying that joke to a few of his black friends discussing, say, how suddenly its "cool" for some White People to act like they're all about Civil Rights by supporting Obama. The person says the line as a way to jokingly insinuate that many of the people supporting Obama were people who still harbor racist views but just try to hide it. They all laugh at the joke out of the notion satire of white culture and hidden racism.
Get a white guy talking with some of his friends while out fishing saying how he can't stand this new nigger in the office that is constantly playing his stupid rap music and has the audacity to be dating a white woman. One of them takes that as a perfect opportunity to tell his new joke and they all laugh at the notion of hanging a nigger in a tree.
Finally take a college aged kid, also white. He's with a bunch of friends of mixed races, sexes, orientations, and religions hanging out in the dorm and drinking a little bit. They've all began telling jokes to each other, basically moving farther and farther into offensive, raunchy jokes as they all try to top each others reaction. One girl just finished telling a rather lewd dumb blonde joke, the next was a dead baby joke, and his jewish friend just busted out the "What do you tell a black jew" joke. The college kid then comes out with the Hallmark joke. Everyone laughs and jeers, acknowledging the shocking offensiveness of it delivered with humorous intent.
All three of those situations uses the exact same joke. All three of them have entirely different context, with the individuals telling it and laughing at it doing it for various reasons. In one case its based on irony/hypocrisy, in one its based on racism, in one its based on offensiveness.
I think if someone came up to my girlfriend/wife and goes "WOW, I'd love to **** you right now. Drop this guy and let me tear that ass up". I would be pissed regardless who said it and why. So context does not matter.
Really? Regardless?
So if some jackass had done something like that the other day and pissed your girlfriend/wife off, so the next day at the bar your wife's sister or friend comes up and says it in a manner that's jokingly mocking the story from the previous day, you'd be pissed?
So if you're out with your wife/girlfriend and she's dressed to kill and a good friend of yours who is happily married comes up and says it in a joking manner, trying to get a rise out of you and causing her to laugh at the insincerity of it, you'd get pissed over that?
Which still, doesn't even TOUCH your previous logic....which is that if you've EVER said something lewd about a girl in ANY context you would have no right to be pissed if someone did that to your girlfriend, because you've done it before.