Denigration is the accusation that is made to another person that can cause it to impair their honor, dignity or reputation, that is, it refers to saying in public, or writing negative things against the good name, fame and honor of a person; especially when what is said or written is false. The act of denigrating consists in staining (symbolically) the fame, reputation or opinion of someone. therefore, this act presented in the question is considered denigration.
Its true that we don't owe them nothing however if we want to make this world a better place where people live in peace and alongside each other then giving a few pounds to charity or volunteering and helping out the needy can really make a change.
