When I visited Budapest I also visited Memento Park, which is located outside of the city. It has a large collection of statues from the communist era. In that case you get a lot more info than a simple plaque explaining the context and history, while also isolating them in one location instead of keeping them all over the city. I think that if you were to leave them in their original spot in the city, even with a plaque, it still represents some kind of endorsement of the people or thoughts it represents.