Possible meanings are 1) the word "their" refers to their enemies. Alternate translation: "With their own hands, they hung princes" or 2) they tied each prince's hands together with one end of a rope and tied the other end so the prince's feet could not touch the ground.
This can be stated in active form. Alternate translation: "they have shown no honor to the elders" (See: [[rc://en/ta/man/translate/figs-activepassive]])