But it might equally well be the other way round. It could be that life IS fundamentally fair, but that by Human action (or inaction) we have collectively made it unfair. You may slur the "innate natural reaction" an emotional neurotic issue, but the fact is that it IS innate, and innate in all Humans, (unless, as you say, they are psychotic).
Actually that is very true. Ultimately everything we ever experience is the result of our own actions. That's karma. But when we try to isolate one event from another with an expectation that we should be treated fairly in it because it appears that we have no prior contact with the people or things in it we're going to be disappointed since karma can come to fruition from past events that have no apparent connection to the present circumstances. That expectation is neurotic and it is no slur to recognize that it is. It's just reality.