Practicality. It is excessive for client code to calibrate library logging level. It’s ok to do it in logging configuration, but having an entry for every library there is also excessive. It is reasonable to expect that dev/staging may have base level at DEBUG and production will have base level at INFO, so that a library following the convention will not require extra effort to prevent log spam in production. Yes, we have entire logging industry around aggregation of terabytes of logs, with associated costs, but do you really need that? In other words, are we developers too lazy to adapt the sane logging policy, which actually requires minimum effort, and will just burn the company money for nothing?