All great people including Sir John A MacDonald deserve a public place, even with their tarnished deeds.
Those tarnishments deserve equal space on their plaques and not be vandalized by thugs. If they are to be demolished or moved to a museum, that should be done by the same authority who granted them space.
The movement against Sir John A. is a biasedly one-sided dislike. Those tarnishments had a willing accomplice in the Catholic Church which seems have been forgiven or ignored.