If not dialogue, what

I was puzzled this morning to hear about the debate, whether Columbia's University decision to host Iranian President was right or wrong. How can an institution grant a space for someone to speak, if that person holds points of view that are not shared by others? Also if that person behaves in ways that others don't find fair, acceptable, right? But then, if an educational institution leaves out of its campus those that hold points of view that are not shared by others - the challenge becomes to identify who are the "others"that indicate what points of view are the 'right'ones. Who will define what is fair, acceptable and right? That is a further challenge. Specially if we take into account that there may be multiple perspectives from where to evaluate it. What is right for some is wrong for others. So what do we do with all those who don't think and act as we like it? As I look back at what I've been taught at school, how history dealt with this problem, I see that depending on the power available, and of the threat perceived, sometimes it was solved using force - guns, fire, encarceration, expulsion. The spectrum goes from one extrem - extermination of the other - to the other extrem: denial of the presence, pretending the other doesn't exist. In some rare cases, though, the way to deal with differences was peaceful yet persistent, searching for understanding and dialogue. An example thereof are the bushmen of the Kalahari, who have as a rule to talk and talk until an agreement is reached that satisfies both parties. Gandhi, Mandela, M.L.King are a few of those. Pretending the other doesn't exist, closing doors to dialogue, to listening, may be a bit too much of magic thinking - that the differences that I don't hear of, don't exist, and will soon dry off. I have had so far a different experience: the less that I listen to something, the louder it gets.