There is always a tendency to clean up our history for the kiddies. Pitcairn's actual words were, "Lay down your arms God damn you, ye rebel bastards, and disperse!" "Bastard" was the favorite epithet of the era because in so many cases it was true. It was the Golden Age of Illegitimacy.
The damage done to the arsenal at Concord was minimal. Smith and Pitcairn's troops threw some powder and ball into the river and spiked a few cannon. Benjamin Franklin, ever the wit, later said that a troop of American schoolboys could have done more damage.
Smith and Pitcairn were not prepared for what happened next. It was a long and bloody ride back to Boston with every thicket spouting fire. Definitely a bad day for the Brtish.
It is the grave of several British "redcoats" who were killed that day.
The grave is very well cared for and given deep respect.