There are a number on this forum that are not in unity with you as far as God's word goes and are in opposition with your perception of many scriptures. It is doubtful many of us will ever agree with your view as your doctrines have been refuted a number of times here.
You state you offended/caused a brother to stumble and he left because of your words to him, yet you maintain you did not do anything wrong and now state your brother was not a brother at all because he saw something different than you do. We don't know what it was he saw that you maintain was incorrect and those details would be nice to know.
Did he believe in Christ and Him crucified and raised from the dead? If so, like it or not, he is your brother. Nothing really indicates to us he was in the wrong except you implying that he is not in line with the Church instead of you saying he was a weaker brother that was offended.
Does this "unity unseen in the world" mean that agreement will be on all of God's word according to what you believe, or is an agreement to disagree allowed such as the case with the separation of Paul and Barnabus over who to take along with them?