She said:
And here’s a man who found out just how fantastic it is, also, when HE picked up a Tony for his performance in "Two Trains Running", currently on Broadway as the first African-American Supreme Court Justice -- actually the ONLY African-American Supreme -- no, that’s not true, uh ...[Laughter and applause from audience.]
I forgot! I forgot!
The "joke" is, of course, that Clarence Thomas currently serves on the Supreme Court and is also African-American. But, because Thomas is a conservative, and does not support liberal causes, Goldberg (a liberal) does not consider him to be African-American.
I realize that Goldberg's joke will be defended as being a harmless attempt at humor, but it's really just another example of how people in politics routinely demonize and diminish anyone who disagrees with them.
It's one thing for Goldberg to disagree with Thomas' political views and judicial rulings: that sort of disagreement can be expressed in a dignified and respectful manner. But it's simply vicious to suggest that, because of his politics, Thomas shouldn't even count as African-American. Even in jest, it's wrong for Goldberg to encourage people to think the worst about those who don't share her views. There's already too much of that in politics, we don't need any more of it.
After all, it wouldn't be fair if someone were to make an analogous joke about Goldberg. For instance, suppose someone were to say: "Hey, I think it's great that the Tony Awards -- the highest award in American theatre -- are being hosted by someone who isn't even American! It's a real score for diversity!" (The "joke" being that liberals are considered un-American.) Such a joke would also be out of bounds, for the same reasons as Goldberg's comment.
Unless Goldberg is making fun of people for questioning the racial identity of their political opponents -- and it doesn't sound like she was -- her joke is inappropriate. It's unfortunate that she made the joke, and that the audience applauded her for it.