How smart do you have to be to realize that your words/deeds have consequences? How dumb do you have to be not to care what they are?

It is not about intelligence, it is about culture. In American culture fx the ideal is to "do it you way", be a "mover and shaker", be a "go-getter" and generally not care about what others think about it. The results (for you) is all that matters. That is alien to a lot of other cultures, and when people from other cultures try to imitate it they usually end up with something that is best described as a parody.