Alway: please discard the stawman.
Current modern humans are not capable of true world peace, because they lack the cognitative capacity for it. They have a dunbar's number of only around 200. In a reality of 6+bn people, it is impossible for them to have complete understanding of every other human, and their roles in society. As such, it is impossible for them to fully cooperate perfectly. Inefficient and incorrect abstractions such as group identities and stereotypes are currently required for the level of social complexity we currently enjoy.
For humans to surpass this limitation without resorting to a regime predicated upon the use of force, humans will have to fundamentally change in a radical fashion. After that, they wouldn't be human anymore, anymore than australopithicus is. They may call themselves humans, but they won't be us.
The process of that change over time necessitates the slow but steady death of the older and less fit (for the current local maximum) individuals. If we want world peace, it means the death of war. If we want post scarcity, it means the death of poverty, and obscene wealth.
If we want world peace, that is genuine and not dystopian in nature (applied through force, to forcibly silence dissenting voices to maintain the unity of vision and purpose) it means the death of stereotypes and small group identities.