It looks like Amazon is starting to hide some reviews to protect against data scraping bots, and in some cases it is affecting real (non-bot) customers.
Were you signed in when you got the message? All of the sorting / filtering / search options are showing up fine for me (as a signed in user).
There are many layers to consumer supplement confusion - seeing marks like NSF Certified for Sport, USP Verified or even eGMP on a bottle are a good start, but there's also the risk of buying counterfeit products on Amazon/eBay, storage (hot warehouses, shipping during summer months, etc.)