Instead of my supposing or assuming, I'd rather you speak for your own position. Pretending to be a different person may be a fun exercise, but it doesn't get me any closer to understanding that person's motives or thoughts as they are.

The point behind the exercise is specifically to avoid an oppositional dialogue. It is a way to flex the muscles of empathy and authentically arguing an opposing position is one way to get there. Supposing and assuming is 100% the point. It's a shortcut to the frontiers of one's knowledge.