what the heck is Polarization anyway?

[godwide_void]

I think Ra brings in some terminology here:

the manifest self - when one interacts with another being
the unmanifest self - when one is sitting in one's room thinking awesome thoughts

71.5 The activities of meditation, contemplation, and what may be called the internal balancing of thoughts and reactions are those activities of the unmanifested self more closely aligned with the metaphysical self.

The manifest/unmanifested self terms make perfect sense and I see how they are co-dependent on one another. The thoughts the unmanifested self thinks lead to the actions the manifested self executes, and from those actions executed the corresponding reality is created, and that reality created by the manifested self will lead to the formation of mental constructs (feelings/emotions, perspectives, biases, thoughts in general) by the unmanifested self, which in turn will lead to further action by the manifested self determined by the thoughts created from the previous interaction between the two, which will perpetually continue in a loop of each sustaining the existence of the other!

and Ra also talks about Wanderers coming back to 3rd Density to INCREASE their polarization

52.9 The Wanderer, if it remembers and dedicates itself to service, will polarize much more rapidly than is possible in the far more etiolated realms of higher density catalyst.

this is consistent with your assertion or premise that one needs to have the veil/illusion of separateness to develop the sense of Service-to-Others, because the 'other' is much more real and 'separate' in this density.

if all is seen and known as One in higher densities, there is a more difficult grasping of the concept of 'other'. In 3d it is most real.

Precisely! Everyone looks, acts, thinks and feels differently but it needs to be recognized that it is just one being wearing different masks present in every interaction. I try to see every post I read here as the literal channeled words of the Creator through different "nodes"; it's probably alot easier for us to view each other as one being considering the fact that we are simply exchanging our thoughts with no semblance of appearance attached to these words through this internet forum. Face to face however, the illusion of separation would be a bit more difficult to breakdown but managing that I presume is a great step in the right direction.