I ctrl-fed this. Only 2 paragraphs in and tremendous factual inaccuracy there. 90 or 120 hz would be appropriate where average people can't detect the change anymore, but some people can distinguish minute frame changes even beyond that because different people have different eye characteristics.
I'm sure some people can't distinguish 48. I'm sure some can distinguish 120. People are different. I personally don't notice the difference beyond 90, but I can easily notice a difference between 120 and 60.
This is false. A human eye can detect changes at 60Hz, for sure.