There are multiple such exhibitions in different countries and I hope you don't mean that they all use prisoners bodies??
And at least for the German exhibition Körperwelten all bodies are donated willingly and I don't know of any accusations that they stole somebodies corpse. So how is it disrespectful if those people willingly donated their bodies?
I personally found the german exhibition extremely fascinating and informative and highly recommend it to everybody who can stomach it. ... and only if the exhibition only used willing participants instead of prisoners bodies of course.