Would you concede that "repulsed" might be too strong a word? I learned from my father (BLESS HIM!) that as long as a man's approach is genuine and gentlemanly, open scorn is never an appropriate response. Regardless of whether I find the man attractive or not, I am generally open to an appropriate compliment or an appreciative smile. I am only repulsed by behavior that crosses the line and becomes crass or presumptive.
Not really. If I am standing in a room with a man who I do not find attractive and he is behaving pleasantly or ignoring me completely, there is no issue. Behaving in a kind or friendly manner is welcome. If he makes advances, I feel like backing away. I don't think that's a rare instinct.