Blue/purple blacks sounds more like a color temperature issue with your projector than something in the video transfer. Have you had yours calibrated recently?
The animators are also the "filmmakers." Film is a collaborative medium.
Further, the movie is intended as an homage to classic animation, and those old cartoons were chock full of in-jokes like these. I doubt that Robert Zemeckis was unaware of them, or objected to them. The decision to censor...