Just my opinion on this matter (as well as other cancel culture issues)
The good that Sir John A MacDonald did, should not be hidden from history...but neither should the his bad decisions.
As a veteran of more than two decades of service to our country, both domestically and internationally, I've seen first hand how dangerous it is to erase or hide history...and I've seen the growing disrespect for our own war memorials, by people who have no respect for our past (good and bad).
It is our duty to ensure that future generations can learn about our history (both good and bad). Most people don't go to museums, and to hide this monument in a museum, would effectively erase the ability of future generations to learn in a fully public setting...instead, this monument should be displayed in a very public space, side by side, with a monument for residential schools. These monuments should have protective fencing around them (to prevent vandalism)...outside the fencing (so the public can read it) there should be an abridged summary of his good and bad deeds, so that future generations can learn!
The ancient Egyptians quite frequently erased people and their achievements from history...and now those things are lost forever...and most recently, Isis has actively worked to destroy history in the middle east...history that I've personally seen, while overseas on deployment...that history is now gone, forever!
History must be presented equally, and not hidden away, or erased...it is not our right to erase or hide history, because we don't like it!
This is just my opinion, and you are all free to like or dislike it as you please.