Why do your "obligations" contain hideous penalties?
They no longer do. When Masonic ritual was developing in the late 1600s and 1700s it was quite common for legal and civil oaths to include physical penalties and Freemasonry simply followed the practice of the times.
In Freemasonry, however, the physical penalties were always symbolic and were never carried out. After long discussion, they were removed from the promises in 1986.