we, and I'm included here, keep thinking and referring to the waiting room as the black lodge. Yes it's creepy in there, no it isn't the realm of pure and foreboding evil. 

The only imagery of the black lodge we are given, ever, in my opinion, it behind Sarah Palmer's face and during the birth of BOB scene in part 8. The white lodge is shown behind Laura Palmer's face. The black and white space the giant watches movies in is more of a go between akin to the purple dimension. It allows the good beings to interact with 'reality'.

just my interpretation