There were probably also other human-like primates at a similar time to Neanderthals and it stopped us from fucking other homo-sapiens who were dead or very obviously ill.

When we were a tribal species we were unlikely to travel much at all in our lifetime and encounter someone who looked different to us so this instinct would have been beneficial. But now that we're a global species we encounter people who look different to us often and this same instinct, compounded with cultural prejudice is holding back our development. We must learn to deal with it and our long standing hate so that we can become more genetically diverse as a species and as a result improve the health and intelligence of our offspring https://www.independent.co.uk/news/science/people-born-to-geneticallydiverse-parents-more-likely-to-be-taller-and-more-intelligent-says-study-10358706.html