I don't really see the issue. The page is just pointing out several anti-patterns with useEffect.
The one talking about fetching data recommends a 3rd party library to make it simple but tells you how to avoid certain issues if you want to go the route of implementing your own fetching.
The POST example talks about how some people will modify a state variable to tell useEffect to send a POST request when you can just do it directly.
Maybe it's not to the depth of your liking but I wouldn't call them rubbish.
The one talking about fetching data recommends a 3rd party library to make it simple but tells you how to avoid certain issues if you want to go the route of implementing your own fetching.
The POST example talks about how some people will modify a state variable to tell useEffect to send a POST request when you can just do it directly.
Maybe it's not to the depth of your liking but I wouldn't call them rubbish.