What is ironic about the words of the second group of aliens in paragraph 45-53?

d. murder of a son and cooking the son for a feast

procne murdered her son and served him to tereus, her husband and her son's father. she did this out of revenge. tereus raped her sister, philomela, and cut her tongue out to keep her from talking. philomela managed to communicate it to procne and procne sought revenge.

tantalus murdered his son and fed him to the gods because he was angry with the gods. the gods punished him by putting him in a pool of water that evaporates when he tries to drink and having fruit hang just out of his reach.

the answer is industry