As far as I understand they're talking about the internal storage mechanics of ClickHouse, these aren't user exposed JSON data types, they just power the underlying optimizations they're introducing.
[1] https://www.postgresql.org/docs/current/datatype-json.html
Are you arguing that since Clickhouse is a database like Postgres, there's no point for CH to exist as we already have Postgres? Column-oriented databases have their uses.
Wow, that escalated quickly. You are reading too much into my comment. You should read the comment thread from the beginning to understand which question I'm replying to.