Although Esperanto is not yet available as system language on Android, Tibetan is also not supported on most of devices. Users can change language using in-application selector or using external tools. It doesn't matter, becouse are not many applications in Tibetan language (see p.3).
This push reguest is about F-Droid website, there is no browser in repository, which supports Tibetan language, but at least Fennec and Firefox Klar supports Esperanto and provide in-application menu to change language.
Argument "we will not remove languages" is also invalid - Tibetan language will not be deleted, but moved to staging.f-droid.org; in similar way old applications are moved to f-droid archive repository.
Esperanto is world language, Tibetan is regional language with limited use.