That's actually an interesting question. For whatever reason the idea that someone might be brought up wanting to respect others, open doors, help strangers out, speaks honestly, is somehow old fashion. It might help to explain why there was such a divide over this Superman. If you're brought up in a cynical environment, where the outlooks are bleak, no-one can be trusted and strength is the only value worth measuring, then it's kinda of easy to see why Snyder's Superman would be appealing to some people. But if you're wanting someone who stands for something good, conducts themselves in a way that's respectable and goes out of their way to inspire others, then that Superman is not for you. This discussion about 'old fashion' make me wonder if today's audiences simple aren't use to the idea of someone being good because that's who they are.
I was in a park waiting for someone the other day near a big family who were having a birthday barbaque when one of the women who had just bought some ice creams for everyone came over to where I was standing and asked if I wanted one. Maybe this type of gesture was far more prevalent in the past, but because I was brought up in a world where 'stranger danger' was instilled in me I was taken aback by the offer. So, maybe Superman doesn't need to be this super complex character, maybe he just needs to present us with an image of what a good person is. It might mean him not being the most interesting character, but if you walk out of the theatre standing up a little straighter, with your head a little higher, and feeling more positive about yourself and other people, then maybe that's all he needs to be. Not every character has to have this dramatic story arc, filled with tension and suffering, sometimes simple is the best option.