@Mr-MaPSaBino games can only load the languages that are available as files so if you find the files it doesn't matter. Games don't check on Steam for language but it's obviously easier to find on Steam.
Yeah idk why staff always say that. I understand not wanting to search for language files themselves but they could just say "buy the game or find language files on the internet" especially since there's a whole spanish guide on the server I don't see why it would be an issue