Not all edits are of equal weight; most of it looks like non-content-based edits, like adding/reorganizing categories. Not to say these contributions aren't valuable--this sort of thing is certainly important--but the article quite overstates his impact.
Actually, to follow up on that, there've been a few articles about him, and on Quora[0], the author of a WaPo article[1] says "Of the site's nearly 5.7 million pages, Pruitt has edited a staggering one third."
If this guy is correct, the edits are sufficiently spread across different articles for him to have touched 1/3 of them. Still obviously not the same as writing, but it puts the headline in a slightly less absurd light.
Well, to be fair, the title doesn't say he wrote it. Just that he's behind it. Which to me doesn't have any clear or even vague meaning. If someone asked, I couldn't tell them. But it is vaguely arguably true, I think. I've seen much worse.
CBS News. I don't even really notice sensationalized or misleading headlines so much these days, until they're pointed out to me.
Perhaps this guy's contribution count represents one-third of a top-contributors list, and the author conflated that with "all of Wikipedia" out of laziness? Curious that "Steven Pruitt" (or any usernames that look like they might be owned by him) doesn't even show up on any of Wikipedia's own lists:
