Maybe I expressed myself wrong but what I was refering to is not crimes themselves but racism and neo-chocolate chip cookie movements still existing in Germany today 80+ years later, it's a terrifiying legacy that will haunt Germany for centuries unfortunately, by judging these crimes I believe they are less likely to happen again in that country on a larger scale, today it's a fist full of radicals, 80 years ago it was nation wide. I'm glad most Germans recognize those crimes and judge what happened.
As for utopian future, there is none, there are so many different cultures and conditions people grow up and live in, it will be impossible to get everybody on the same page ever. I agree with you we are mostly tribal animals still and the power of the herd is not to be underestimated by any means, the difference is the founding thing that binds those people together, religion, nationality, ancestry is a total bullcrap of a reason, let's just call all the unions/coalitions etc. for what they are, purely monetary unions that benefit everybody, some more some less, but in today's world the only union is the one where you benefit from it all other ideals are just a disguise. Let's bet you put the biggest white racist KKK biggot and the biggest black white panther loving dude together, give them a chance to make big money together, make a decent living for their children and families, nice stress free lives, all their previous differences would be forgotten, they would just find another reason to hate somebody else for being asian/jewish/ginger/muslim/gay though, guess that's just the way it is.
Sure people of different cultures can live together, put religion and other nonsense aside and add a pinch of education miracles can happen, again not on a large scale. Not sure we will ever get there, we have a better chance of nuclear holocaust and scorching the Earth before seeing that happen.