The site is JeanPain.com and was my late mother’s site. She has a PhD in Conversation Analysis and was an eminent psychotherapist in the UK. Every post on the site was written by her (except the obituary on the front page) and goes in-depth with long essays on her life story and psychology.There is not a single post on there that could in any possible way be described as “thin content”, so I have no idea why it was turned down. What do I do as there seems to be no way to get any help (and since there is nothing to be changed on the site, no point in resending it for review).
As far as I can see, this is a challenging site to be approved for AdSense. The challenge in part is the very high standards for things to do with psychological health — relating to the “Your Money or Your Life” standards for credentialed expertise; generally decent search results (and thus AdSense qualifications) are limited to well established and recognized institutes and organizations. See third party YMYL issue discussion below.
But, you rightfully may answer, Jean Pain IS credentialed — and after some searching i indeed found about her published works, including an offering of her book through Cambridge University Press. But it took some work — someone else with the Jean Pain name is involved in something to do with wood chips and horticulture.
Ok, then I went to the next question: “What kinds of ads would serve well on this site?” and came up with the realization that commercial ads on your site would detract from the site’s purpose and messaging. Let me put it another way: If you were an advertiser, why would you want to appear on this site? (If you can answer that question then my next one would be: — Good, now why don’t you go out and show the advertisers the site quality/traffic and content, and then sell some advertising directly. If you can do that you’d earn far more than any brokered program.)
In other words, you may be right — Jean Pain is properly credentialed and the site isn’t “thin” — but does that make it suitable for AdSense? I don’t think so. The bots/human reviewers may have given you an incorrect answer to denying the site from the program but personally I don’t think they were wrong in saying this site (along with 95 to 96 per cent of others which seek AdSense these days) has been declined.