Nobody is supposed to even touch the wrecks, so I'm not sure what you're prying.
It is true that there are some wrecks you are not supposed to touch. (When I dove the wreck, Gunilda, I was informed that the Canadian government prohibited touching it.) It is permissable, however, to touch most wrecks. In fact, in order to penetrate a wreck it is almost always necessary to do so.
As for needing a pry tool, it is handy to move hatches or pieces of wreckage that might otherwise impede passage or pose an entrapment problem. I recently made a dive on a fishing boat that sank a couple of months ago. I needed a pry tool to get into some compartments so that I could salvage some personal items that the owner wanted to get back.