https://docs.mongodb.org/v3.0/reference/method/db.setProfilingLevel/#db.setProfilingLevel states that is

Modifies the current database profiler level

It also allows you to set the "slowms" threshold but it does not make it clear that this setting is applied to profiling on all databases. IE, you are specifying two parameters, one of which is applied to the "current database" and the other which is applied to all databases. This should be stated explicitly.