An awful lot of laws were made hundreds of years a go, Middle Ages ...they were made by the landowners (think Sheriff of Nottingham) to protect their property and belongings etc, so the peasants who had to live off the land and poached the landowners fish, deer, boar etc in order to live, faced harsh punishments....thats why sentences like this are seen as severe in comparison to those mentioned in the OP...
Considering this stuff had been "lost and buried underground" for so long the sentence is ridiculous...