Trinitarians, have you considered Col 2:9 ?

They have considered it, they just don't understand it. Trinitarians are Trinitarians simply because they do not know any other way to think about God. They have always heard the word "Trinity" and believe that it is part of the Christian gospel. They have never heard the Oneness message. It is not that they are opposing the truth, but that they are ignorant of the truth. They need to be taught, not scorned. I pray that those who believe false doctrine will realize that they're wrong and come into the truth.