At first glance, this piece being here makes sense, in a roundabout way:
Battery Park is so named because a gun emplacement here during the War of 1812 defended what was then the village of Burlington; it is directly in front of a statue of General William Wells, a Congressional Medal of Honor recipient for his valor at Gettysburg (not that this type of gun would have been used in either situation, but you get my drift).
The rough-hewn marble plaque laid in the ground tells a different story:
"Toward the death of war & boundaries between countries
Aug. 18, 1987"
To my mind, a somewhat strange anti-war statement.