I'm back. Great replies as always on here, which was why I posted in the first place.
I think I was really bemoaning the importance of identity (and the rejection of others) and the hierarchy of these; 1. species, 2. gender, 3. colour etc etc (arrange in an order appropriate to yourself). "Hey man - we're all humans. let's just get along together ok?"
I'm thinking that having identities are evolutionary biological drives and probably very hard to resist. I also completely recognise that I'm able to think that they shouldn't be as important as they are, because my identity is part of a perceived norm in my society. I have white/class/education privilege. If something about me defined how everyone else reacts to me, I'd probably think it was pretty important too.
I was also thinking how we tend to give others identities from visual cues (probably another biological imperative - does it/they look like a threat) - hence the importance of skin colour and style of dress in assigning identities to yourself and others. That could be why there has been such shock and vitriol following the Brexit vote. Those who we thought were the same as us (nationality, colour, language, education) are now the 'other' because of their expressed views and assumptions of being the same identity/tribe have been demolished.