Happened to me when I saw a book on the US site, I wasn’t able to see all reviews, but there was a button to sort-of “apply” to get approved for seeing all of them.
It took five days, then I got this email.
Interestingly, they’re not doing this on the European site, you can still see all reviews there.
Maybe it’s lazy on my end, but my first guess is that it would be in order to prioritize and normalize the AI summary. Basically a dystopic move towards trust me bro