“Prior to capitalism, the way people amassed great wealth was by looting, plundering and enslaving their fellow man. Capitalism made it possible to become wealthy by serving your fellow man.” - Walter E. Williams
I agree with Dr. Williams, but I see why the statement doesn't satisfy some people. They don't object to "serving your fellow man," but to the desire to become wealthy.
Part of that comes from the historical circumstances Williams mentioned; the "looting, plundering, and enslaving." In many hierarchical cultures transitioning to democracy, the assumption remains that that's how the wealthy get that way. Justice seems to require the redistribution of wealth, with little thought about wealth creation.
Even in cultures with a long history of markets, the perception persists, with good reason, that the system is rigged. Whether it's intellectual property law, the choice of where to build a road, or government regulations and subsidies, it seems that the well-connected, who are often the already-wealthy, have special advantages.
Or, the government creates incentives that may misdirect resources. Home-building may be encouraged. Or bailouts of bankrupt companies. Or the building of unnecessary infrastructure or production of unnecessary war weapons. In these ways, some will get rich not just off the backs of their fellow taxpayers, but off of future generations living in a harmed environment.
Finally, there's the moral or spiritual aspect of wealth that turns some people off. The pursuit of material goods as a sign of status is alleged to generate feelings of emptiness and unhappiness. And such pursuit may lead some to make ethical compromises or commit outright crime. And for what? When you die, you can't take your possessions with you.
On the other hand, if you're reading this you've achieved some degree of wealth -- access to the Internet -- that was inaccessible to even the wealthiest of us a few decades ago. So the condemnation of wealth always seems to be relative, and the conception of "basic necessities" evolves to accommodate greater societal wealth.
So even if you prefer to live modestly, if you also want others to live longer, healthier lives, wealth must be generated. And such wealth is brought about most swifty, and most justly, in free-market capitalism, where individuals are free to serve each other.