The idea of needing to come up with use cases for generics is baffling. The existence of generics in numerous other languages already support of plethora of use cases. I really don't get that statement at all.
Because generics have been around for decades, and anyone who can't be bothered to look into the use cases for a feature that spans numerous languages over that time period doesn't deserve the time it takes someone else to spoon feed this information to them. This goes for the author of the article as well.
I think this is a fair question. We have a lot of pseudo-intellectuals here that think 90% of their job isn't writing business functions. Not having generics in Go has not hindered me at all in performing the objectives of my business. Everyone wants generics, no one knows why. When I had generics in my previous two roles where I used Java and C# respectively, I can count on two fingers the number of times I needed them, and once was because a library forced me to.
This is such a troll'ish statement, but I'll respond anyways because maybe you actually are just that uninformed. Without generics any number of libraries that utilize generic function blocks - Func [1] in C#, Callable [2] in Java, etc., and do things like return the function's type parameter as a method result, would not be possible. This is exceedingly common, at least in libraries. If you want to know how common, let me refer you to my friend http://google.com.
Just because something isn't valuable to you, personally, doesn't mean it's not valuable. As in all aspects of life, not everyone is you.
I am another developer who has never really suffered as a result of a lack of generics. Personally I really like how dead easy golang code is to read and understand. God forbid golang become a language where untold amounts of logic can be packed into a single line of code, resulting in near mathematical levels of complexity which always require more time to understand. Like most complex concepts in life, I suspect the number of developers who can effectively use these tools is rather small compared to the number of people who think they "need" them. But hey, I'm a vim programmer who doesn't like to have to rely on a bloated IDE to be able to deal with the code that I am interacting with so I might be a minority.