I don't think most people even stop to consider whether the death or suffering they caused to animals is wrong, unless they actually see it happen (everyone has a negative reaction to seeing a dog beaten, for example). But yes, it's very frustrating when you talk to people about it and give them good arguments (which they have no response to) and they still show no sign of changing anything even in minor ways.

Most people just don't think about things, and don't care about issues that don't have a direct impact on their lives. Sad but true. Still, it's worth bringing the issues up with people as much as you can, because even if it has no effect most of the time, it will sink in for someone and will make a difference. I mean almost every vegetarian first had the issue brought to their attention by another vegetarian or by an activist. Rarely, if ever, do people just have an epiphany and change their lives without another person planting a seed.