There's a world of difference between expelling the immoral brother and killing someone who doesn't believe as you do. The difference is hardly subtle but still, it manages to escape some.
I also notice that as of yet we still have not been provided with Scripture supporting the murder of those anyone else deems to be heretic.
1 Samuel 16:7 But the LORD said to Samuel, "Do not look on his appearance or on the height of his stature, because I have rejected him. For the LORD sees not as man sees: man looks on the outward appearance, but the LORD looks on the heart."
Yes indeed. Jesus answered the question of who are his brothers.