[takes a breath, plunges in]
One of the really appealing things about circuit bent stuff is that it can be pretty much whatever you want it to. It can exist strictly on an isn't-this-noise-cool level, it can be an engaging technical puzzle (I'm thinking of Graham working out all that lovely stuff on his SK-5's), you can put some godawful glitter paint on it and call it art, or you can laboriously make the world's most gorgeous re-casing and say it's just design.
Aside from playing shows, I use circuit bent stuff as components for larger art pieces. I've done a few installations with audio from a glitching Yamaha or Casio that forms the background layer for whatever else is happening. So in that context they can be considered art. I don't think that they're inherently art on their own, or at least they aren't for me.
The term 'post modern' is a fake idea. Some number of years back I took a class about post modernism and read all of the heavy articles on the topic from the 70's on. It is a colonizing parasite of an idea that, at its worst, is used in a proprietary fashion to claim a piece of culture or art or whatever as post modern and, at its best, serves to needlessly complicate a simpler idea.
[whoah.] I kind of came on heavy there, huh?
I guess if you wanted to, you could take one of the many definitions of the term and make circuit bending mesh up with it pretty well, though.