The thing is, none of the suggested alternatives can do what pickle does, and the article focuses on a narrow (albeit ubiquitous) use case: serialisation of untrusted data.
There are still legitimate use cases for pickle, especially when storing, caching, or comparing objects that can't easily be serialised with say, JSON or TOML. It's a question of using the right thing for the right job is all, and pretending like JSON is a comparable alternative to pickle doesn't help anyone.