I'm going to try explaining something fairly complicated I learned in a 'development and inequality' subject I took.

Capitalism is really beneficial if you live in a country that has an advanced economy. If you live however, in a place that has a 'traditional/backwards' economy, you reap less benefits and the system takes advantage of you in order to sustain the advanced economies. To be at the top rung of the 'development ladder' requires somebody else being at the bottom.

Advanced countries like ours take advantage of the lesser developed countries. Sure, it's voluntary. Both sides agree to it. The terms and conditions of these deals weigh heavily in the favor of the advanced countries though. Because of their 'advanced' status, the advanced countries have more bargaining power (more carrots and sticks) to employ against the 'traditional' countries. This results in some parasitic deals in which the advanced countries suck the life (resources, environment, loans with crazy unfair conditions) from the traditional countries.

This isn't that hard to picture. Every time primitive values and societies come in contact with modern/advanced society, the primitive loses. Traditional locals aint about to stop that beach hotel on the island from being built.


Now, all of that is at the international level. At the level of the country, capitalism breeds inequality in both similar and different ways. If you want me to get into it, I will, but for now I'll just say that it has to do a lot with ever-increasing income inequality which leads to social fragmentation (people hating on people - rich vs. poor, black vs. white, socioeconomically oppressed identity group A vs socioeconomically privileged identity group B, etc. etc. etc.).

So that's why it's a problem, at the international and country levels.