I'm with you on this post except for calling out the Catholic church. It's the overwhelming majority of Christians who believe in the Trinity, even if it was brought in because of Catholicism. Go to almost any protestant church and try to say Jesus isn't G-d but only His son and see what kind of reaction you get. I've been "coming out" about my non-trinitarianism lately and it's a tough road.
RE: What is the origin of the Trinity?