That argument would apply to production backend databases but I don't see how it really applies to logs. It's like they just copy and pasted a generic argument

That argument would apply to production backend databases but I don't see how it really applies to logs. It's like they just copy and pasted a generic argument regarding structure data without taking account of the context. Logs tend to be rarely read but often written. They also age very quickly and old logs are very rarely read. So putting effort to unify the schemas on write seems very wasteful versus doing so on read. Most of the queries are also text search rather than structured requests so the chance of missing something on read due to bad unification is very low.