John Gill Commentary Lamentations 5:12

"Princes were hanged up by their hand: The faces of elders were not honored." — Lamentations 5:12 (ASV)

Princes are hanged up by their hand
According to some, as Aben Ezra observes, by the hand of the servants before mentioned; however, by the hand of the Chaldeans or Babylonians; see (Jeremiah 52:10) . Some understand it of their own hands, as if they laid violent hands upon themselves, not being able to bear the hardships and disgrace they were subjected to but I should rather think this is to be understood of hanging them, not by the neck, but by the hand, could any instance be given of such a kind of punishment so early used, and by this people; which has been in other nations, and in more modern times.

the faces of elders were not honoured ;
no reverence or respect were shown to elders in age or office, or on account of either; but were treated with rudeness and contempt.