Are "camp classics" good movies or bad movies?

I won't attempt to answer the question, but I've been thinking about it recently, because I keep catching bits and pieces of The Bad Seed on cable lately. I'd seen the movies many times before (as should be obvious from some of the references on this blog), but I hadn't seen it recently, and I was shocked to discover that it's one of those movies that I simply cannot stop watching once I come across it.

Here's a review that says most of what I would say about the movie. The acting is, in many instances, so over the top that Al Pacino's performance in Scent of a Woman looks restrained by comparison (Hooo-ahhhh!). There are, however, some genuinely compelling and chilling moments, particularly the scene in which Christine and Monica watch -- and the audience hears -- what happens to Leroy while Rhoda practices her piano piece offscreen. And the two scenes which feature Eileen Heckart as the bereft and drunken Mrs. Daigle are really fascinating and quite good.

How all the elements of a camp classic come together is a mystery to me. Watching The Bad Seed again after several years has convinced me it's not just -- or not always -- a matter of transcendent badness. The badness is often there, to be sure, but looming over it is the shadow of a greatness that announces its approach with occasional blasts of thunder and lightning, but never really arrives on the scene.

[Edited to correct typo in the title]