In the past few months, I've seen a lot of speakers online and in person, who have shown the ability to have good civil and thoughtful discourse. I want to be like them when I grow up! Much too often, many discussions that I've been a part of or witnessed are really only arguing our point of view and expecting a conversion in their thinking or ideal. How wonderful it would be if we first truly understood the others perspective. I'm not saying to believe the other persons perspective, but put aside your own intention in the debate and only truly look at things from their perspective.
I believe the quote asks that we who want to make changes in this world must do this first and then articulate an opposition to that perspective that would include the other person's understanding of that opposition. In simpler terms, being able to use the person's reasoning in a way that would enlighten their understanding of the opposing viewpoint.
Taking the time to understand someones intention and their comprehension of the situation that is being debated will help to foster good-will between the two parties and increase the likelihood of having a good debate and it not just end in a shouting match. Not only do those tend to never end well, but the likelihood is usually that both parties will remain mired in their own viewpoints and more likely be even further apart in their opinions of that particular debate.
If conversations can begin with mutual respect for the subject matter then those will be, by far, the most pleasant ones you'll have. Respect for the person's differing opinion can help that conversation, but in my opinion, is not necessary. Keeping the emotions in check will be a necessity and will most likely feel like an impossible and daunting task, especially if the subject matter is a personal truth for you. If that is not possible and those emotions can't be reigned in, then hope for an amicable discussion is fruitless.
I'm hoping for the kind of dialogue that both parties can be proud of and a fostering of kindness for humanity. One that allows each other the space to be who they want, think what they want to think and feel free to live their lives in a way that gives them the most happiness. Imagine what the world would be like if we could do that. :)