That's an incorrect assessment

Lexicon schema are not enforced, they are a tool for social coordination, and most implementations are very liberal in what they accept

https://www.pfrazee.com/blog/lexicon-guidance

> isTool: true; isRule: false; meaning: undefined

ActivityPub by contrast lacks such social coordination and many apps are reusing the same schema for very different concepts, leading to its own form of over-complexity