Quite possibly none of them are 33rd degree craftsmen. Most probably many not even beyond the 3rd level. But they are always in quest for bigger power.

33 is a power number, and they believe this kind of sacrifice would propel whoever did the sacrifice (or whoever the sacrifice was done for) to higher levels.

Classic example is Jim Belushi. After his brother John "died" at 33, his career took off. Did he off his brother? Did the brother sacrifice himself for him? Did the parents decide which kid to be sacrificed and which to be propelled? We don't know.