Another dev who doesn’t show respect to what has been done and expect a particular language will do wonders for him. Also I don’t see this is much better in term of readability.

Where do you see the lack of respect? The author wanted to learn how gzip works and chose to implement it in a language they like to do so. As a learning tool, not because the world needs another gzip decompressor.

he does mention https://github.com/trifectatechfoundation/zlib-rs not just https://github.com/madler/zlib, but it would be interesting to hear from those developers also