Does AI Content Hurt SEO? What Google Actually Says

Short answer: no, not by itself. Google has said publicly that it rewards helpful content however it's produced, and that using AI is fine as long as the page meets the same quality bar as anything else.
Longer answer: AI makes it very easy to produce the kind of content Google does push down. That's where most of the horror stories come from.
The policy that matters
Google's spam policies include 'scaled content abuse': producing lots of pages mainly to rank, with little originality or value for readers. It doesn't matter whether those pages came from a model, a content farm or a spreadsheet template. Sites that published thousands of near-identical AI pages were hit by exactly this, and a lot of them haven't come back.
What ranks
The pages that hold up tend to have things a model can't invent: first-hand experience, original data or screenshots, a clear point of view, and an author readers can check. Google's quality guidelines describe this as experience, expertise, authoritativeness and trust. You don't need to memorise the acronym. Just ask whether your page tells a reader something they couldn't get from the ten results above it.
A sensible way to use AI for content
Use it for the parts it's good at: outlines, summaries of your own research, first drafts you intend to rewrite, title variations. Keep a person in charge of the angle, the facts and the final edit. Check every claim, especially numbers and anything about another company. And publish at a pace someone can actually review.
Where humanizing fits
Editing an AI draft into a more natural voice helps readers stay on the page, and engagement matters. But rewording can't add expertise that isn't there. Treat a humanizer like WriteHumane's SEO/Blog mode as the polish on content that already has substance, not a substitute for it.