Any being that tries to destroy my individuality is evil. Whether you call this being Source, oversoul or God, it is an evil being that tries to murder us all. I don't believe in such a being, and I think that the evidence gained from psychical research negates all oneness theories.
Raimo, I'm thinking that you need to look at this from a different angle. Personally, I do have a suspicion that completely merging with (let's call it 'God') God is the ultimate spiritual state that we can get to develop to. Whether that means entire loss of our individuality I don't know and don't think anyone else knows for sure, that's at a level of spiritual development that is beyond the grasp of the human mind. There will be things happening there that might seem contradictory to human reasoning but in the spirit realms apparent contradiction can, and is, overcome.
For example, look at what (on average) NDErs say about time. They claim that either time doesn't exist, or is in some way fundamentally different, for themselves and the environment in which they have the NDE. To folks that haven't had that experience that can read like a huge contradiction -- after all, in the NDE, things are changing and that, to our human minds, implies time. Yet still the NDErs insist that time as we know it doesn't exist in the environment they are in. So this is an example of the limitations of the incarnate human mind.
In my own NDE (can be read here
Peter N -- NDE) I did have experience of 'merging' with other minds and that didn't in any way compromise my sense of identity, in the sense that I was losing something. Far from it, my sense of identity grew exponentially in ways that isn't easy to describe, but it really was very, very beautiful (I would much rather be that than be what I am now). So here there is an example of merging with other minds and not losing individuality, but also becoming more than your individual sense of self in ordinary human life. See, what counts as 'individuality' is quite malleable in the spirit realms -- so you can't really look at the issue from a restricted human mind viewpoint, trying to approach it that way just doesn't work.
There was a point in my experience when I completely merged with the 'light'. At that point I just disappeared. What humans would regard as 'me' just wasn't there any more. This was a very brief phase of the experience but wasn't in any way frightening, quite the reverse it was beyond belief astonishingly beautiful to just be that 'light'. (I wouldn't object to being that even if the cost was my human identity.)
As to psychical research negating all oneness theories I don't think that is a correct view. Most of the channelled literature that I've read at the very least points in that direction. Some specifically imply that this might be the 'end game' (so to speak). Geraldine Cummins, channelling Frederic W.H. Myers, in
The Road to Immortality and
Beyond Human Personality strongly points in that direction and I'm inclined to agree with Myers. In particular his description of the gradual removal of human personality from a soul ascending the spiritual realms does strike me as pretty well spot on. The human mind -- as a restricted individual identity -- gives way to the Group mind and on and on it goes as one moves upward. I think this is the bit that you are missing in your thinking. It's like you're reacting, as a human being, against the loss of that identity (I do get that, I think I see where you're coming from) but what makes you so sure that you will always possess that identity -- as it gets eroded in its restrictive-sense, and expanded in other directions, you might well be open to other possibilities that for now, with a human identity, you would reject.
Likewise
A Course in Miracles (ACIM), Helen Schucman self-purportedly channelling Jesus, quite explicitly states that the end game is complete merger with God. However, it doesn't say that means you lose all sense of identity -- Jesus says that explaining what that merger is like in terms that a human mind could understand is outright impossible. And that's the point, whatever it amounts to it will be well beyond the grasp of the human mind. ACIM also says that when you get to the point of complete merger God will do it gently, no murder, no evil. Very gently and only if you are ready, not before. (Though if you're not ready that will have consequences too.)
So in all the points I'm trying to make are:
(1) If complete merger is the 'end game' then there is no way that we can know what that really means. Extinction of individuality, maybe yes, maybe no, maybe some, in our terms, apparent contradiction in between.
(2) When it comes to the merger it is very likely that you won't be possessed of what we would regard as a human mind -- so it really isn't possible to any of us in possession of a human mind to say what kind of decision we would make when that human mind (identity) is gone, to be replaced by something else, very likely expansive beyond what a human mind can visualise.
(3) In that state your understanding will be different, and so your ultimate decision might well be different too.
Personally, if I had the option, I'd go for merger whatever the consequence. To be one with God would be some prize and I'm pretty sure it would be a state utterly breathtaking in its beauty and magnificence -- even if 'I' wasn't there to realise that (damn contradictions :0) ). I'd just have faith that what God would do would be for the (an) ultimate 'good' and I'd be happy to trust in that.