I am open to learning from others here how to improve the social side of my communications in dialogs like this.

Given that the confusion between you and RobinZ was dispelled below, a good piece of advice might be to be careful when you think you have an interlocutor trapped between a simple theorem and a hard place; it's often turned out (in my experience) that some condition of the theorem doesn't apply to the particular case the other person is suggesting, and that the divergence of opinions can be traced elsewhere.

Most of the regulars here are smart enough to get the point on preference reversals when pointed out— the fact that RobinZ said he understood but was talking about something different should have counted as evidence to you.