Can you provide us on what basis they are ranked or the site used any algorithm script?
I don't think anyone or a single person can rank a website's ratings or reviews based on an algorithm or script used by a casino because as far as I know, most casinos are closed source. Furthermore, in all of GamblingBro's reviews, he primarily based his score ratings on many criteria like RTP, Deposit and Withdrawal restrictions, KYC, VPN, Bonuses and Rewards, and so on.
Personally, I always check his website[1] whenever a new gambling site is mentioned in this topic to see if there are any red flags to be aware of before making a deposit.
[1]
https://gamblingbro.com/I understand that the ranking of the site on GamblingBro are based on one person's experience but i don't give much importance to the numbers. The important thing for me is that he has explained in-depth many gambling sites and if you are new to gambling, this site will help you get detailed insight about every famous gambling site.