They disable commemorative cannons so they do not have to worry about some damn fool stealing them or monkeying with them.
Yes, I know that’s the ‘why’, I merely question if it is more detrimental in the end than beneficial. — It also has the built-in assumption that (a) people are defined by the lowest common denominator, and/or (b) people are not [and cannot be] mature, self-governing moral individuals [that is, eternal adolescence and never mature].