I think the mural ought to stay, as an example of early 20th century art if nothing else.

Regarding "revisionism" - the research of history is an ongoing process. New information is discovered on a regular basis, so yes, we do revise history as we learn more than we knew before. Sometimes it is hard to let go of long-held ideas about the past, even when new facts show those ideas are clearly wrong.

But of course, we all know that history is written by the victors.