There is a reason why even in mathematics people like to operate on concrete examples to get an intuition. For many, concrete is much easier to understand than abstract.
That's the less important point. The more important point is that making your code generic often involves more trickery which makes the code more complex, even if you only use the code once or twice - so that's just effort wasted.
The fact that parameterization is a proven abstraction doesn't mean it's good everywhere. Same as I don't agree with the "Clean Code" way of creating a myriad of 4 line functions.
Yes, good programmers won't make these mistakes, you can totally handle them. But when arriving at legacy code or open-source projects I greatly prefer to find under-abstraction rather than over-abstraction.
To be clear, I'm not against generics, I just agree with the parent of my original message. I'm worried people will overuse them and I don't want a whole laundry list of Rust features in Go. I'm very happy about libraries with type-safe generic B-Trees.
