It's not libel; it's just an opinionated argument that you dislike, so much so that you want to stop the other person from speaking.
It's intent on changing public policy by persuading voters with argumentation. This is the most protected class of speech. That it publishes ugly true facts about individuals (which is also protected!) is an incidental step towards the author trying to paint a persuasive political narrative.
(I can't help but want to break this down. You say it's misleading, but the case docket is hyperlinked inline with the text you say is misleading—that's far more than adequate in US jurisprudence. No "reasonable person" (a technical standard) is misled on a fact that's plainly disclosed, just one click away. You say the criminality is in the "distant past"—but the person's felon status is current, ongoing, and in fact relevant to the author's line of arguing, which is that these nonprofits are a form of "laundering" federal government grants to people the federal government otherwise disqualifies. You think (and I'm sympathetic to this) that crimes committed 20+ years ago are not strongly reflective of the current human. But, this is a subjective interpretation—not an objective truth beyond reasonable debate; and the fact that the US government itself disagrees, by permanently disqualifying felons shows how ludicrous it'd be to argue, in a US court, that "he's a convicted felon" is speech without social value).
Let’s revisit the original comment.
> 370 Falsely and maliciously accusing another. Sec. 370.
Falsely and maliciously accusing another of crime, etc.—Any person who shall falsely and maliciously, by word, writing, sign, or otherwise accuse, attribute, or impute to another the commission of any crime, felony or misdemeanor, or any infamous or degrading act, or impute or attribute to any female a want of chastity, shall be guilty of a misdemeanor.
Literally only have to imply the commission of a false or degrading act, or imply a woman is a slut. Why do you think that would be historically if not to keep people from killing each other over saying things they didn’t like.