Have you ever been jealous and experienced that the world is unfair?
It is unfair. There is no natural justice built into it. There will always be people who are more beautiful and smarter than you. Safer and happier. There will always be those who are affected by illness and injury. Children to abusive parents with addictions. Victims of violence and crime.
But that does not mean that those who are more fortunate need to be richer. Their lives are not more important and more valuable than anyone else's. This system that allows a few to exploit the work of the many, reinforces the world's injustice. But capitalism is created and built by people over time. It is possible to disassemble it and create a new system based on the principles of justice and equality. That is sustainable and accounts for the individuality of people, their different needs, desires, and dreams.