I'm quite sure that not *everybody* reacts negatively to peoples egos all of the time. For example, I think women would mostly be the ones to sometimes be attracted to a mans ego. She might see him as motivated - a go-getter of sorts, or the "alpha male." But I'm no psychologist.
I'm sure it could be the other way around, men attracted to egotistical women, but I think that would be even less frequent. These days it's all about pretending to respect eachother and to not be self-absorbed.