By its very definition, libel is always untruthful.
In law, defamation (also called calumny, libel, slander, and vilification) is the communication of a statement that makes a false claim, expressly stated or implied to be factual, that may give an individual, business, product, group, government or nation a negative image. Slander refers to a malicious, false and defamatory spoken statement or report, while libel refers to any other form of communication such as written words or images.
Semantics aside, here is the actual explanation for the ruling:
Noonan appealed to a three-member panel for the First Circuit, which initially upheld the ruling by Lasker. But last month it reversed itself on the libel claim, saying Noonan could pursue that part of his lawsuit because of a relatively obscure 1902 [Massachusetts] law.
The law says truth is a defense against libel unless the plaintiff can show "actual malice" by the person publishing the statement.
In ordinary discussions of First Amendment law, "actual malice" refers to the standard established in the landmark 1964 US Supreme Court decision in New York Times Co. v. Sullivan.
In that context, it means a plaintiff who is a public figure can win a libel suit only after proving that a journalist knew a published statement was false or acted in reckless disregard for the truth.
But in the Massachusetts law cited by the appeals court, "actual malice" means "malevolent intent or ill will," said the panel. Noonan might be able to persuade a jury that the company demonstrated ill will; Baitler had never referred to a fired employee by name in a mass e-mail before, and jurors might conclude he "singled out Noonan in order to humiliate him," the court wrote.
So we're talking about:
1) A state law.
2) A ruling that simply allows the guy to sue; it's not a final verdict by any means.
3) A very specific instance, that will eventually be settled in court anyway, as per 2).
So, I don't think this is anything for journalists to get overly anxious over, in truth.