I don't know about the T4 program, so I'll have to look into it.

However, whilst I suspect I agree with the impetus behind your observations, I think you're in danger of throwing the baby out with the bathwater here.

To state so categorically that there is no border between the self and the other (or that there shouldn't be at least) ... in other words that we should love our brother/sister as ourself, to paraphrase a well known exhortation ... is to impose a border in and of itself.

It precludes the possibility of a state of flux, whereby one is, at one and the same time, both individual and part of a greater whole.

A group consists of individuals ... yet it still exists as an phenomenon in its own right. At the same time, however, remove every individual from that group and no group remains.

Things aren't quite so "No black and white only shades of grey" as you seem to be suggesting, I don't think.