Ethical character or culture (ethos) for Aristotle builds on hexis. The latter is most commonly translated as habit. Earlier, I called it emotional constitution. It is an acquired, active disposition to respond or act in certain ways that seems to be centered in the emotions.
Actions, reactions, and choices — as well as many things that just happen to us — cumulatively contribute to the formation of a more long-term emotional constitution that then becomes directly responsible for the tone of our responses to things, and that we can only change with major, prolonged effort, if at all.
People respond to situations based on a combination of emotional disposition (hexis), their constellation of commitments (ethos), and deliberation and choice. It does not generally make sense to blame someone for acting in accordance with their acquired disposition, but at a broader level, people are partly responsible for the formation of their disposition. People are responsible for their choices, unless they are coerced or misinformed. People are in principle responsible for their commitments; bad commitments usually involve more than simple misinformation. But misinformation, lack of good opportunity for learning, and emotional disposition should certainly be taken into account in charitable interpretation of commitments, too. (See also Willing, Unwilling.)