What kind of metaphor does the ballad "the hanging tree" in The Hunger Games 3 contain?

The original book was sung to Katniss by her father when she was a child. Once she sang at home, Mom heard and scolded her severely, and she never sang again. The meaning at that time was no longer just a simple description of a pair of tragic lovers. Judging from the lyrics, the person who sang this song was the young man hanging on the tree. It mainly reflects the Capitol's brutal tyranny. This song also echoes another plot in the novel. While hunting, Katniss saw a couple fleeing from the capital. The man was killed by the pursuing security police, and the girl was raped. Tongue made Aivax servant.

Katniss has experienced so many tragic events in the past two years, so she sings this song again, remembering the countless lovers who were deprived of love by dictatorship and war, and the countless people who lost their loved ones