Funny how everyone loses their mind on such a petty matter thus being hostile. Hidden areas are meant not to have arrows to begin with. If they had arrows then what is the function of having the name ‘hidden area’ in the first place? In fact why not just put a big billboard with neon lights directing you towards it. That would be an amazing touch.
Calling someone a douchebag for not sharing the information ain’t that bright either. Really, what do you gain from that? Just to get there? Then what? You achieved immortality or finding secrets to your virginity or something? Wouldn’t hurt if you ask something like “What map do you find the passage to that area?” but did you? Nooooo.
Just in case you didn’t know or just being too lazy and hoping for a walkthrough like you did on FAQs, there are others hidden area without arrows. Such as in Crystal Mine (2f or 3f can’t remember). Is it so hard to be explore the map, every inch of it?