Trimming the book is one thing, and I agree with you 100% on both examples. Removing the conclusion in a way that completely alters the message is another.
This happened with the Heinlein book "Podkayne of Mars" -- the original ending had one character dying and another character changing course because of it. The editor thought it too heavy for a kids' book and directed a rewrite where everyone lived.
Years later a new print included both endings and staged an essay contest to decide which is the "right" ending.
Years later a new print included both endings and staged an essay contest to decide which is the "right" ending.