Two of the “Sins that cry to Heaven for Vengeance”, I.e. sins that are so serious you may ask God to kill the sinner, are underpaying or withholding wages from workers, even if both parties “consented” to an unfair wage; and just general oppression of the poor.

One of the other sins is sodomy, but I will cherry pick to ignore that because the other sins actually matter materially whereas this one is just being invasive for no reason lol.

It was also Catholics that explained and reaffirmed these sins as serious.

Catechism 2434 - A just wage is the legitimate fruit of work. To refuse or withhold it can be a grave injustice.221 In determining fair pay both the needs and the contributions of each person must be taken into account. "Remuneration for work should guarantee man the opportunity to provide a dignified livelihood for himself and his family on the material, social, cultural and spiritual level, taking into account the role and the productivity of each, the state of the business, and the common good." Agreement between the parties is not sufficient to justify morally the amount to be received in wages.