The point you are responding to is not about using th stdlib, but implementing it. If you look at the stdlib itself, it adds lots of functionality without too much code, from scratch.
Crypto stuff - yes. Reflection, AST processing, concurrent hash map - I'm not convinced. Some parts will be terser than others.
The standard library doesn't implement typical business logic. So it's not the best benchmark.
Not to mention the lack of reusable data structures.
The std lib is disciplined about using safe Go ideas except in the exceptional cases. I feel like it’s nothing that is enforced by the formal spec of the language, just that the std lib has an exceptional emphasis on making it really hard to walk away with misconceptions.