Zman,
It's not quite that simple.
Please remember that the DNA found in JonBenet's panties was mixed. The major component matched JonBenet's DNA; and if the minor component was contributed by a single individual then the other Ramseys could be excluded as the donor. However, if a third individual had contributed to the mix then the Ramseys could not be excluded. Therefore, the Ramseys are only tentatively excluded.
There are a lot of other variables to consider, including the authenticity of the information known to the public. Also, according to the documents flashed on the screen by Michael Tracey in the U.K.,and screen-captured by some of us who post here, apparently DS could not be eliminated as the contributor, even though the Ramseys, the Whites, and Mervin Pugh could be tentatively eliminated. There are other considerations, including Alex Hunter's cryptic comment, "You'd be surprised if you knew who we were investigating now."
We the public don't have the results of the DNA analyses to help determine if there was a fifth person in the house that night who had been invited in by a Ramsey. And that person's DNA is in the mix.
BlueCrab