No apologizer in history has ever voluntarily confessed to any other of his misdeeds. These subsequent mishaps are only pointed out by others -- because the miscreants never really admit to what they have done wrong in the first place.
If Fareed Zakaria didn't actually do this plagiarism, could he very well announce to the world "I didn't do it; I didn't even research or write the article"? No. Zakaria wouldn't want to burst the bubble atop which he is floating.
Zakaria is a trustee of Yale, which takes a very dim view of plagiarism and suspends or expels students who commit anything like what he did. If the Yale Corporation were to apply to itself the standards it expects its faculty and students to meet, Zakaria would have to take a leave or resign.