The Question and Answer section for The Mayor of Casterbridge is a great resource to ask questions, find answers, and discuss the novel.
I would say it was unethical, even within the context of those times. Michael Henchard, for example, offers to sell his wife and daughter to the highest bidder. Michael will regret this decision.
Henchard makes a name for himself in the hay and corn business and rises up to become mayor of the town.
The theme of suffering in the novel links with the theme of fate and the nature of the character ,for they all contribute to the sufferings and misfortunes of Henchhard .