Delete deceased actors?

Is this a commmon practice? When I read John Candy and Madeline Kahn have been completely removed from this film, at first I was disgusted. It would have been a true honor to release this film--if that ever happens--and dedicate it to these two people with their voices in it. Later, I wonder if it was for legal reasons. Or perhaps there is a reason we're not even sure of.

In any case, as a John Candy fan, it's disappointing his voice is being completely eliminated from the film.