Why doesn't the ghost box have as bad a reputation as the Ouija board since people attempt to use both of them for the same purpose?

I would guess it's because it's much less well known. "Ghost Boxes" are relatively new on the seen, and seem to be popular only among the gadgety gimmicky ghost buster crowd. Almost everybody knows what a Ouija board is. Also, the Ghost Box just doesn't have the hands-on humanity of a game where people all grab a pointer and move it around. The ghost box is passive, while the Ouija board is an active exercise to "raise the dead", so to speak. That registers more emotionally with people than operating an electronic gadget.

Seance's are seen as almost respectable, Tarot and psychic readings are available online, astrology is widely accepted, it just depends on your upbringing. They are all pretty much the same thing, an attempt to find a greater meaning to existence, or belief in such.