Denylists itself make sense… Centralized ones absolutely not

In its early days IPFS was being pushed as a anti-censorship tool, obviously blocklists/denylists is the opposite of that. But it’s all a moot point, you’re linking to a discussion from 2015. AFAIK denylists were already implemented e.g. https://blog.ipfs.tech/2023-content-blocking-for-the-ipfs-stack/