Please point out where Ann C. said he was not.
Matter of fact, point out in the column where she says "Roberts is the wrong pick".
She implies that because he doesn't have a long "track record" of legal opinions as a judge, that he could end up being liberal as Souter. She doesn't say he isn't conservative, she just indicates that he might not be -- her preference obviously being for someone with more outspoken views in a longer record of jurisprudence, like Luttig or Edith Hallan Jones.
Reading the commentary, it's clear the the commentators admire Bush for choosing someone who will take the Court further to the right, and also someone for whom it will be very difficult for the Senate Dems to find any traction to argue against. Double whammy.