Sorry, gr, but oneness gets no claim to being Christian. Oneness by definition denies the triune nature of the Godhead. This necessarily implies something is amiss when it comes to
who Jesus is and
who the Holy Spirit is. We either worship the God who is, or we are idolaters. There is no middle ground.
This does not mean a Christian must understand the Trinity at the depths that some others may understand it.
The Trinity is not beyond the grasp of any true believer.
You cannot read the Scriptures plainly without seeing the Trinity in evidence. Christian reason dictates that when you read Scripture it cannot be teaching that there are three Gods and one God for that would be a contradiction. Thus, this same reason dictates you dig deeper, seek the instruction of your church, review what the church as declared in history, as well as the interpretations of the community of believers, for we worship and interpret in community.
Those that deny the Trinity are to be rightfully considered as outside the faith for they are without excuse for not coming to a proper understanding of the doctrines made clear in Scripture about the very God they claim to worship.
As to the Pinnock reference, it is made to show how the view of one of the fathers of open theism lends itself so easily to Mormonism and Mormon-like notions. Point being, if your views are being hailed by cults, and your group's founders become the cult's co-belligerents, that should give you great pause, if nothing else. Just sayin'.
AMR