I’d think everything depends on the individual’s psychology. Some people are simply hard-wired (whether by nature or nurture) to seek their own best interests. Some get it into their minds that sincere discussion as equals somehow smacks of compromise, and as such is akin to Neville Chamberlain’s appeasement of Hitler. Some even see the word “altruism” as the silliest of social concepts (and come to think of it, I think I’ll write an article on that one).
So in my opinion, one must first determine whether the other person understands the concept of altruism (even if it’s not in their vocabulary). If they don’t understand the concept and are apparently unwilling to give it the time of day, then you’re wasting your time trying to educate them.