Oneness comes in many guises. It is the standard basis of New Age spirituality. Oneness is also the extracted essence of Westernised Hindu, Buddhist, Sufi mysticism and the like.
And it is the core of that highbrow, relativised, symbolic, amoral-leftist derivative of mystical and ritual Christianity, popular among intellectual liberal 'Christians' such as Rowan Willams (sometime Archbishop of Canterbury).
Oneness is (as a minority possibility) taught and supported by the Establishment. For instance some major state bureaucracies, educational organisations and private corporations offer Oneness teaching and/or therapy under various titles such as counselling and 'mindfulness'.
And, at the intellectual and high cultural level; there are variants of the eclectic, syncretic 'perennial philosophy' derived from Theosophy with its anything-but Christianity tendencies - e.g. Prince Charles's Temenos academy or the Schumacher society.
Positive features on oneness can be found in mainstream Leftist newspapers, on TV, in movies - its practitioners are at least acceptable, and may be accorded official honours and prizes.
What are its characteristics? Oneness teaching is against 'the Self'/ Ego, and against 'thinking'.
It regards all men as One, indeed evrything that is - is One.
The intention is to lose the thinking self into an apprehension this ultimate One-ness.
(In practice, this state-of-being is intermittent, recreational and therapeutic; and in-between times the Oneness practitioner will typically be well integrated into 'normal life' - which nowadays means The System and all it entails.)
Why does Oneness fit-in-with The Establishment agenda of evil?
Well, quite simply because the thinking Self - when that Self is our divine nature inherited as sons and daughters of God - is the only thing about us that stands outside of The System.
The thinking of this divine Self is what we use to discern, judge and evaluate in accordance with God's values. The thinking of this divine self is what motivates us from a source in harmony with God's creation.
Naturally, The System wants our divine, thinking Self dissolved away into nothingness!
And is happy to encourage any philosophy which assists in such work!