Apparently, when you are nominated to the Supreme Court, you are not only responsible for the wacky and irresponsible things you say, but you are responsible for the wacky and irresponsible things that anyone associated with you, in any way, says.
Judge Alito at one point belonged to a group called "Concerned Alumni of Princeton" (CAP). He has no recollection of this, but he did put his membership with this group down on an application back in 1985. Because of this, it's apparently fair game to comb the record of what anyone associated with that organization has ever said to try to pin on Alito. This is in spite of the fact that, as the New York Times noted back when this was first raised, there is no indication that Alito played a major role in the group (in fact there is really no indication that he played any role at all).
As for the CAP, the group (which went out of business in the 80's), doesn't seem to have much of a footprint on the web. All one finds is stuff like this, where someone puts out a couple of sentence fragments, from which they draw the conclusion that the organization was racist, or insensitive, or what-have-you.
Now, I frankly doubt that CAP was racist. The names I hear associated with the organization, William Rusher and Dinesh D'Souza, may be firebrands who like to say controversial things, but they aren't racists. As for being insensitive, it would hardly surprise me if group's magazine, Prospect, said some things that pushed the envelope. D'Souza was in his 20's when he edited the magazine, and people in their 20's tend to be like that. (Here are Rusher's thoughts on the controversy, by the way).
But the better question is why, for heaven's sake, we are talking about things said by some members of a group Sam Alito might have belonged to 20 years ago? As Jonah Goldberg points out, Senate democrats don't want Alito on the Court because they don't like the way they think he will vote on the issues. However that isn't a good enough reason to defeat the nomination, you need evidence that Alito is pure EVIL. However he just doesn't look or sound demonic enough on TV, and the dems have scoured Alito's extensive written record without finding any cloven hoofs. So we move on to best friends, and then just-friends, and then friends-of-friends, until we can find someone who has written something from which we can tease an outrageous sounding sentence fragment or two. Then it's off to the races.
By the way, Kennedy wants to delay the nomination until William Rusher's papers over at the Library of Congress can be subpoenaed and examined. According to the NYT article I linked to above (okay, here it is again), this was done by their reporters, who failed to find any smoking guns. But now Rusher is making the papers available, so I suspect that this will quickly become a "never-mind" moment.